APRIL 6, 1900.] ..

.. MODERN FIELD ARTILLERY. (Continued ftorn page 412.)

12-PoUNDElt Gu~ AND ~QUIP)lENT . TBE 12-pounder " separable gun as manu~ac-ed by Messrs. Vickers, Sons, and . Maxtm, t~ 't d is of special interest, because, as 1ts name ~my. e 'the gun as well as the carriage can be taken

tmp ~es, as shown on the engravings on page 437. 00 pteces, ,., are of such limited weight, that men These par1.10

I

Fms. 61 TO 63.

E N G I N E E R I N G. shoulder which engages with a corresponding shoulder on the barrel. I t is provided with gun-metal liners at the front and r e!l.r, to facilitate mounting and dismounting. The rear por t ion of the jacket projects beyond the barrel, and into this portion is screwed the breech bush, which is pro-vided with interrupted threads to r eceive the breech plug. To prevent overscrew, the breech bush is screwed up against a dead stop formed on the face of the jacket. By means of suitable k eys

.

.

'

.

,it-\

.

.

. .

\' . > . f." t,

: ' .. .

. .

-

I \ \ \ \

\

----

Fig . 66 .

433 ;

other end of the link is pivoted to a shor t crank, which is mounted on the plug carrier , and around the boss of this crank are formed Rkew-gear teeth. The hand lever for actuating th~ breech mechanism is pivoted on the plug carrter, and moves in a plane at right angles to the breech face of the gun. Around the boss of this band lever is fi tted a skew gear wheel, which gears with the skew gear teeth, formed on the boss . of th~ crank. The whole is arranged and proportioned In such

--

---

-

...-_ ....

-----------.,..

'

/ /

I

~= r: C..

'

FIGS. 6 1 TO 66. BREECH MECHA NISM OF 12-POUNDER S EPARABLE GuN.

or mules can ~rry them up mountains. The ad-vantages of th1s arrangement are obvious.

'l'he gun itse~f, of which a cross-section is g iven on page 436, Ftg. 60, consists of two principal par ts -the barrel and the jacket with the breech bush shown ~epara~ed .in Fig. 75, on page 437. The barrel,, m whtch 1s formed the chamber , consists ~iran I~e.r tube, reinfo.rce~ by an outer tube and ste ~ wmdmg. ~he wue 1s protected by a thin tr e ~ube. .The J&~ket, on which are formed the f umhons, dtsmountmg lugs, and the hinge bracket t?r t e breech mechanism, encloses the rear por-Io:o~the barrel, and is passed on from the muzzle :: ~ ~e gun. ~he. fr?nt end of the jacket is

PP own on 1ts mstde cli&meter to form a

tho barrel is prevented from turning when the pro-jectile rotates. To separate the jacket and the barrel for t ransport, the breech mechanism is taken out, the breech bush unscrewed, and the barrel drawn out towards the rear .

The Breech .NfechaniS'In (Figs. 6 1 to 66).- The breech mechanism, which is illustrated in detail above, is opened or closed by tho horizontal movement of a hand lever, so that the same act ion rotates, locks, or unlocks the breech plug, and swings it around the pivot on which it is mounted. The arrangement consists of a link, one end of which is pivoted on a pin projecting from the rear face of the breech plug, so that the link works in a plane }->arallel to the breech fac~ of the gun. The

a manner that when the breech is closed the hand lever lies close up to t he breech face of the gun, as shown on the engraving (Fig. 61). The centres of the link and crank are also arranged so that when the breech is closed the centre lines of the link and crank form a nearly straight line, the p ivot joint at the link and crank being a little past the dead-line centre, thus forming a locking point. This arrangement of centres and pivots, together with the r elative lengths of the link and crank, provides great p ower when opening or closing the breech.

On swinging the hand lever a way from the gun when opening the breech, the crank moves t he link past the locking centre a short distance without

434 causing any perceptible movement of the plug. The further movement of the hand lever causes the crank to turn, and by means of the link r otates the plug, at first very slowly (thus obtaining great p ower), and then more rapidly unt il it becomes unscrewed ; the carrier then moves with the lever swinging the plug clear of the gun. The firing gear is arranged for firing with percussion tube (Fig. 66), and is operated by the link of the mechanism so that at t he fir~t movement to unlock the breech plug, it becomes impossible to fire the gun. An extractor is fitted to this firing gear which automatically ej ects the empty tubes during the opening of the breech mecha-nism. A retaining catch, automatically worked in connection with the extractor, prevents the tuba from being jerked out when closing the breech. The breech block has six threaded and six interrupted segments, in order to give a great er area to meet the strain when firing. Figs. 61 to 63 show the breech mechanism in three positions, and clearly illustrate the arrangement.

The Carriage (Figs. 67 to 70 and Fig. 73, pages 436 and 437). - The carriage consists of the following parts : The trail, the elevating gear, and the axle and wheels, shown separated in Fig. 75, on page 437. The trail consist3 of two trail sides made of steel plates j oined together by a shoe and two transoms. 'fhe front transom forms the be-aring for gun and axle, these bearings being so con-structed that the gun and axle can only be dis-mounted in certain positions. On the inside of the trail sides there are fixed the bearings for the

elev~ting gear. The trail shoe is provided with a socket for taking the handspike, and two h ooks are fixed to the trail sides for securing the brake ropes. The elevating gear, which consists of two bevel wheels and an elevating screw, is provided with trunnions and lugs, and can easily be dismounted by turning the gear rearwards about 90 deg.

The axle is cylindrical, with two lugs, which engage with the outer part of the front transom. The axle can only enter its bearing at a certain angle; and when in po9ition, it is t urned about 90 deg. by means of a lever attached to it. This lever is locked by the trunnion s of the gun, thus prevent ing the axle being dismounted before the gun is removed. The wheels are of the usual construction , and k ept in place by drag-washers and linch-pins. During the 'dring, the wheels are attached to the trail by brake ropes, to prevent them r eYol ving to the rear.

Limber (Figs. 71 and 72, page 436).-The limber consists of a framework constructed of steel and attached to t he axletree by suitable brackets. It is provided with a hook at the r ear for attaching the gun-carriage when t ravelling, and in front is a bracket for supporting the pole. The pole is attached to the axle by a bolt, and is fitted with a crossbar for transport. On the underside of the pole is a prop for supporting the limber when unloading. The ammunition chest s, which are fitted to receive 12 charges and 12 shells, t ogether with the necessary primers as well as spare parts and tools, are made of wood, strengthened by steel bands and angles. The boxes are secured to the limber frame by key-bolts, passing through projections on the front and through lugs fixed to the framework of the limber. Each box has two studs a t the rear, one on each side, which enter suitable bearings in the outer angles of the framework. The boxes are fitted with hinged lids and cat ches, and at the ends are handles for carrying. The wheels are of the same construction as the ones used with the car-

nag e. Par ticula.r s of 12-P otiiTl.der Landing GU/11..

Weightofba.rrel ... .. . ... ... 2lllb. , jacket and breech bush . . . 188 , , mechanism . . . . . . . . . 44 ,

443 , 3 in.

Total weight of gun ... Diameter of bore . . . .. .

Length of bore . . . . .. , gun, total ...

ba.rrel . . . . .. " , jacket .. .

. . .

...

. . . 43.45 in.

. . . 48.5 ,

. .. 45.5 ,,

.. . 30.05 " Weight of charge .. .

, , projectile

. . .

. . .

, carrtage . . . . . . .. . . .. Angle of elevatio? . . . . . . . . . . ..

depression . . . . . . . .. Height of axis of gun from ground_ ...

13 5 oz. 12.5 lb. 513.0 " 17 deg. 7 . ' 26 in.

Weight of limber complete, w1th 24 rounds of ammunition, spare parts and tools . .. ... ... ... . .. 747 lb.

D iameter of wheels .. . . .. . . . . .. 36 in. Width of track . .. . .. . . . ... 48 ,

Operations fo> Dismounting the G1.t1t ancl Ccvrrictge.

ENGINEERING. - The operation for dismounting the gun and carriage, so that it may be carried by men or mules, a re thus described for drill purposes :

Take out breE ch mechanism, unscrew the breech plug, and withdraw the barrel towards the rear.

. The tangent sight is now removed, the elevating joint pm yulled out, and the jacket depressed {about 55 deg. ) unti it is stopped by the axle bearings.

The lugs at the rear of the trunnions, which, under normal elevation and depression (17 deg. - 7 deg. ), securely lock the gun to the carriage by engaging corre-sponding bearings formed on the inside of the crosshea.d, have now become disengaged from these bearings, and the j ~tcket is free to be lifted out clear of the ca.rriage.

The elevating gear is secured to the carriage in an exactly similar manner, by trunnions and lugs, and is dismounted by turning the whole gear rearwards about 90 deg. The hand wheel fixed to the side of the trail, and 'vhich is kept engaged with the driving bevel-wheel by a spring, is now disengaged from the elavating gear by pulling it backwards against the spring, and the whole gear can be lifted out from the carriage.

To detach the axle and wheels from the trail, the lever locking the axle to the trail is turned forward about 90 deg. when the trail is free to be removed.

When gun and mounting are taken to pieces the following parts constitute the different loads for transport by men: First L oad {T wo M en ) :

Barrel . . . . . . . .. . .. Second L oad {T wo M en):

Jacket and bush ... Third L oad {T wo M en):

Trail .. . . . . . .. ... FOtt,r th Load {T wo Men):

Mechanism and elevating gear, drag-ropes, &c., cleaning-rod, handspike ...

Fifth Load : Axle ... . .. . . .

Sixth Load (Two M en) : Wheels ... . . .

Seventh L oad ( Two Men) : Ammunition chests ... . . .

Lb. 211

188

200

127

120

140

219 If carried by mules,

as follows : the dis tribution of loads is

First Load : Lb. Weight of barrel . . . . . . . . . . . . 2ll Tools . . . . . . . . . . . . . . . . . . 20 Leather box .. . . . . .. . . . . . . . 10

~addle complete with harness and bridle 50 Total . . . 291

Second L oad : Weight of jacket with bush ... 188 Mechanism . . . . . . . . . . . . 14 Elevating gear . .. . . . 42 Cleaning rod.. . . . . . . . . . . . . . 5 Saddle complete with harness and bridle 50

Total 329 T hird Load:

Weight of trail . .. . . . ... 200 Tools and spares . . . . . . . . . . . . 20 Hands pike . . . . . . . . . . .. .. . 1l Saddle complete with harness and bridle 50

Total . .. 281 Fourth L oad :

Weight of axle . . . . . . . .. . . . 120 , wheels . . . .. . .. . 140

Hanger a . . . . . . .. . . . . . . 20 Ropes . . . . . . . . . . . . .. . . . . 8 Saddle complete with harness and bridle 50

Total 338 Fifth L oad :

Weight of ammunition chest with 12 rounds of ammunition ... ... ... 219

Sa.ddle complete with harness &.nd bridle 50

Total . .. 269 Fig. 73, on page 437, shows the gun mounted

on its carriage ready for firin g, and Fig. 74, shows it taken t o pieces r eady for transport by men or mules, together with assembling tools. Fig. 75, on the same page, illustrates the carriage t ak en to pieces for the same purpose ; i t shows the wheels, axle, elevating gear, handspike and trail, &c., all separated.

(To be continued.)

SOME STATISTICS RELATING TO ELECTRIC POWER PRODUCTION.

By PHII.IP D AWSON . THE g ro wth of electric p o wer plants, and the

more general introduction of electricity, both for lighting, heating, and power purposes, has been very rapid during the last few years, especially in Great Britain. Electric tract ion in part icular, which t ill recently was practically unknown in this

[ A PRIL 6, I goo. cou_ntry, has made . such progress that England, w ~1ch was far ~ehmd other European countries, w1ll soon be leadmg, both in the number and the scale of the installations.

. Five ~ears a~o, when ENGINEERING firFlt con-Slder~d ~~~ ~eta1l the g_eneral subject of " Electric Tractwn, . 1t was practically unknown in England. People st1ll had to be convinced of its advantages and great prejudice had to be overcome. Now ther~ are few left _who question the absolute superiority of the electnc, over all other, systems of traction as applied to tramways.

'!'here is another, and far greater field in which electric traction will render invaluabl~ services. The working of passenger traffic on the overcrowded s uburban an~ metropolitan lines in our great cities, where the diStances are not too great for economi-cally tr~ns~itti~g the requisite electric power, and the serviCe 1s so Intense as to guarantee a fairly con. stant load. Besides the saving in working expenses which the introduction of electric traction on such lines would certainly bring about, it would greatly increase their passenger carrying capacity. On these lines the distances between stopping places are short, rarely exceeding half a mile. The traffic possible on each line depends on the average speed attainable, including starting and stopping between stations. With steam the limit has been re!lched. Practical experiments have amply demonstrated that by substituting electric for steam haulage on such lines, the passenger carrying capacity can be increased by 50 per cent.

Another field in which electricity is rapidly gain-ing ground is in replacing single small steam motors and rope and shaft transmission, in factories and works. All power generating machinery can be grouped in one place and transmitted t,o individual motors installed wherever required. In countries where wat er power is reliable and obtainable with-out t oo great initial expenditure, large electric power plants are installed which transmit energy within a radius of a hundred miles or more. Table I. is of interest in this connection as showing some of the power transmissions which have been success-fully put in operat ion ; it also gives the power and the pressure at which it is generated and trans-mitted.

In t his country it is proposed to instal power plants at t he pit's mouth, where coal is cheap, and to distribute the power for various purposes o~~r the n eighbouring country. The call for electriC energy is becoming larger every day, and th_e power installed in individual electricity worJr:l lS rapidly increasing. The use of polyphas~ hlg~tension transmissions and the success obtamed m the construction and operat ion of rotary converters, has resulted in the concentration of power gene-rating plant under one roof. By this I?e~ns an~ by the use of labour-saving appliances,_ 1t IS poss1ble to greatly reduce the cost of productwn. . .

The object of this, and following, articles 1s to attempt to show the great importance. of properly laying out and working electnca.l statwns, and to describe the various methods which have been suc-cessfully used to reduce the cost of installation and of production. Conclusions will not be dr~wn. The facts being given, readers must by com_parlSon. make their own deductions. A companson w1ll _be attempted between the various systems to b~mg out the good and bad points of each_. Englif!h, American Belgian German, and SwiSs practiCe will be co~sidered, ~nd as far as possible c?mpared, the conditions that obtain being taken mto con-siderat ion. .

Too much stress cannot be laid on the questiOn of the desian and equipment of a station. Wear~ no lonaer in an experimental stage. The use 0 high p;essures and polyphase current~ enables _us to choose the location of t he power statiOn pr~ct1ca~ly independen tly of the net work to be supphe~ w~~ current. In most cases t he question of gettmg nt g reatest amount of power into the smallest amou f of space need no longer be considered. The usef 0 electricit y for traction and power, as ~~11 ~s 0~ lighting, enables a far more efficient utihsatwn the generating pla.nt. . run

Tramways and rail ways are m most cases . day and night. P ower for other purpos~s t~s certainly required at least 12 hours out 0 . ~ 24, and the demand for light is gen~ra~y heavie~ When that for power and traction lS hghtesth.

t ere~ traction or combined power, statiOn IS, d. ' f ble con l fore, working ';lnd~r muc~ more avour~ In

tions than a hghtmg statiOn pure and sunple. 'tal the latter, the reduction of interest on the capl

APRIL 6, I 900] E N G I N E E R I N G. r

= = TABLE I.-DATA m' SOMR Ex1 T n m 'ELECTRICAL Pow&n TRANSMIS. IONS.

NA ~fE OF TRANSMI~ STON.

-

l.auft'en, Frnnkfort (0 er mnn~)

Redlnnd-:, Snl'romenlo, Cat. .. Teluride, Utah Ogden, Salt l .nke Oity, Utah

Fre~oo, Cat. . west Koo~nny, B.C. . I Newcastle, ncrnmento, Cnl. Spiez-Buritdorf, Thun Bern San Antonio, San Bernt\1'

dioo, Cnl. .. .. .. Folsom, nrrnmento . . .I Redlnnd'i, Cat. . . PndernoMilan.

Ni~anra Fnlls, Buffalo Bulte City, Montana ..

Blue Lnke, Cnl. Oene,n, Switzerland . .

Pnchuca, Mexico Mihm, ltnly . . Teluride . . . Santa Cruz, Cnl.

..

'J'iroli, Rome, Italy ..

Lowell, Michigan . . . Three Rivers, Canada . &kersfield, Cnl. . . . . Cordo,a, Argentine Republic Mechnnic,ille, N.J. . . . . Bogotn, Colombia Republi .. Hochfelden, Oerlikon .. Lowell, ~a hun, N.H.

lem, ~.c. . . . . ~lont renl, Canada .. Bulnck, Oerlikon ..

Portlnnd, Ore. . . . . . . Litlle Cotton Wood -. alL

l.al-e rity, Utnh . . . . Big.Cotton Wood-SaiL Lake

CtLy, Ulnh . . . . . . Ynr~e, Italy .. Bodie, Cnl. . . ZuftkonZurich, Switzerland L:l OouleSt. Etienne, Fro nee Les CleesYverdon, Switzer

land .. .. .. .. SihiZurich . . . . . . )!ootpelierBarre, Yt. Cumberlnnd MiUs, Me. Belle\ille, Canada .. Osaka, Japan ..

BollerZurich, Switzerland .. Belenn, Montana Fairhnven, \'t. Harlford, Conn. Welb Oity, Mo.

..

Anderson, S. C. . . llinnenpolis, St. Paul Manchester, N. H. . . Tuscorora, Ne'' .. Cripple Creek, Col. . .

. .

. .

Bet2enried-Weigen, Switzer land .. .. .. ..

5 55 40 35 30 29 26

28 22! 21 21

21

2t

20 20

19 19 18 1 1 1 li 16 16 16 15}..

-

15! 15 15 15 14!

-

14}

14

14 14 13

12~ 121

-

12J 12 12 12 12 11 11

-

' 11 11 11

10.~ 10 10 10 10 10

10

-

(

4,000 1,000 5,000 1,400 2,000 1 000 5,400

160 4,000 1,000

12,000

10,000

4,000

1,800 4,000

2,000 > 10,000 1,600

400 2,000

270 800

1,200 1,500 5,000 1,400

900 550

1,000 20,000

400 2,500

3,000

G7!i 1,000

160 1,300 2,000

1, 00 2,000

400 600 375 135 300

3,530 300

4,000 320

1,600 5,000

775 136 300

500

At Gene On Line. rntor.

300

i 50 800

2,300 'iOO

1,100 500

4,000

1,100 00

2,500 13,500

340

800

1,000 300

700 350 500

1,100 5,500 1,000 2,000

550 700

12,000 6,700

500 330

10,000 12,000

86 6,000

GOO

G,OOO 3,600

' 6,000 5,000

6,000 5,000 2,200 1,100 2,300 2,400

86 500

2,200 500

5,000 10,000

3,5LO 1,100

550 6,300

6,000

30,000

30,000 40,000 15,000 11,000 20,000 15,000 16,000

10,000 11,000 10,000 13,500

11,000 1 1s,ooo} l26,000

11,000 12,000

10.000 20,000 11,600 11,000 5,fi00

10,000 12,000 10,000 10,000 12,000 6,700

13,000 5,500

10,000 12,000 13,000 6,000

15,000

10,000 !i,OOO 3,500 5,000 5,000

5,000 5,000

10,000 ,000

11,000 3,500 5,000

12,000 2,200

10,000 5,000

10,000 11,000 10,000 10,000 6,300

5 ,00~

~ystem of Tmnsmi. sion

3-phnse

11

11 . .

..

11

..

2 nnd Sphnse 3-pha. e

Single phase 3 phnse

11

..

2phnse

3phnse

2 and 3phase 2-phn.se ..

3pha e 11 ..

2 and :3-phn.se 11

Single-phase 2phnse .

" 3 phase 11

11

11

11

11

11

2phn.se 3-phnsc

11

. .

. .

. .

. .

2 and 3phnse

3-phnsc ..

Single-phase 3-phnse . . Sing le-phase

3-phnse 11

"

2 and 3-pha.se 3-phnse ..

11

11 . .

2 and 3-phase 2-phase . . 2 and 3-phnse 2-phase

11

3-phase 11 ..

,

,

11

25

50 00 60 ao 60

40

ao 50 40

2o{ 60

40

GO 40

60 60 38 50

30

4 33

GO 45

50 50

!)0 40

60 60 48

35 60 60 26

50

NA ME OF MAl\ERS.

Allgcmoinc Elek tricitli.ts Gesellschaft, Berlin, Mnschinenfa.br ik Oerlikou.

General Electric Co., Schenectndy. Ditto Ditto. Ditto Dit to Ditto

Westing-house. Brown a.nd Boveri.

Westinghouse.

Ditto. Di tlo. Ditto.

General E!ectric Co , Schenectady. Di tto Ditto.

Brown and Boveri. General Electric Co., Schcnectady. \\' e t inghou e . General Electric Co. , Schenectady.

Stanley Electr ic Company. Societe de l'Industrie Electrique,

Geneva . General Electric Co., Schenectady. Brown and Boveri. Westinghouse Company.

Ditto. Ganz and Co. , Budapest. Sta.nley Company.

Dit to. Genera l Elect ric Co. , Schenectady.

Ditto Ditto. Di tto Di tto.

Mnschinenfabrik Oerlikon. Brown and Boveri. General Electr;c Co. , Schenecta.dy. Stnnley Company.

Ditto. l\Iaschinenfabri k Oerlikon. General Electric Co. , Schenectady.

\V estinghouse.

General Electric Co., Schenectady. Co. Fmn~aise Thomson-Houston. W est.i nghouse. Maschinenfo.brik Oerlikon.

Ditto Dit to.

Ditto Ditto. Brown and Bovc:> ri. Westi nghouse.

Ditto. General Electric Co. , chenectady.

Di tto Ditto. :Ma.schinenfabrik Oerlikon. Westinghouse.

Ditto. Dit to Ditto.

Stanley Company. Ditto.

General Electric Co., Schenectadr .

Ditto Ditto. Ditto Ditto. Dit to Ditto .

Maschinenfabrik Oerlikon.

435 :

t hird , or gas, has been used with very: good res.ults in small plants, especially where coal Is. ex~ens1 ve ; this system will be discussed, and ;).pphcat10ns and results obtained described at length.

A brief consideration of the probable require-ments as regards the supply of power ~hich 'Yill be made in the near future for electrlC traction alone in this country, is interesting. There are pro-bably few countries which present a much larger field for electric traction than Great Britain. At the present moment we have some 400 miles of route on which about 2000 electric tramway motor cars circulate. Besides the lines mentioned, and which are already in operation, there are at least another 400 miles under construction over which approximately another 2000 motor cars will cir-culate.

I t is not probable that electric roads will be as extensively built in t he United Kingdom as they were at first in the Fnited States. There, with some 60 millions of inhabitants, there exist. roughly, 30,000 miles of electric roads and 100,000 motor cars. Owing to our stringent laws and regulations, and the cost entailed by the solidity with which we are accustomed to build, roads would not pay in t his count ry which would be lucrat ive either in America or on the Continent. It is not over-estimating, however, to say that within the next five years at least 2000 miles of electric tramways will be constructed. This would only represent t wice the mileage of surface roads possessed by Greater New York, a city which is still inferior to Greater London both in population and area .

Besides t ramways, there is a field for electric traction on railways. We have large cities, and we centralise our business. There are very numerous steam railways running into the hearts of our ]arge industrial towns, bringing in daily millions of people. Land is very valuable, and there are natural conditions which in many cases would make it impossible for the railway companies to increase the number of their lines. Traffic is, in most cases already so intense that during the busy hours of th~ day t he rail way companies are already running as many trains on t heir City and suburban lines as they safely can, by steam. The use of electric trac-tion would, owing to the rapid acceleration obtain-able wi~h electric motors, enable the rail ways to greatly mcrease the average speed of their t rains, and, t herefore, augment the number of trains by 50 per cent ., if not to double it .

In Greater London and its outskirts we have, counti~g ~11 railways, including the Metropolitan and D1str1ct, probably 1000 miles of track which might advantageously be equipped electrically. The same conditions hold good of other large com-

m~rci.al centres, such as Liverpool, Manchester, B1rmmgham, Sheffield, Glasgow, &c. In t hese towns t here would probably be another 1000 miles to be equipped. The railway companies will soon realise the necessity of introducing electric t ract ion.

(To be continued.}

ARMOUR-PLATES. MANY distinguished writers have held the view

that, not infrequently, the sufl'ering and misery caused by a war are fully compensated for by t he moral elevat ion which leads men to understand that mere money-grubbing, important as t his is for the material well-being of a nat ion, should not be the sole aim of a good citizen. In the present cont~~t in Sou~h Africa we have seen wealthy

outlay, and the sink~g fund, is of the greatest im-portance, as t.he s~t10n and system, which repre-sent .the cap1tal, he unproductive during what pract1cally amounts to from six to nine months a ! ear. .The question of reducing the labour and

~ncreasmg . the econom~ of running the plant ~s a neghgable quantity, compared with the lmportance of .reducing .the interest and sinking

f~nd. Hence, m .older lighting stations, the adop-tiOn of unecononuca.l non-condensing engines and the. absence ?f labour-saving devices. With a statlOn supplymg energy for traction and power purposes, th~ case is very different. Here we have a plant wh1eh is running from nine to twelve

m~nt~ ~year. The question of interest on capital an

1s1mkmg fund, although of importance is often

patriclans, leadmg merchants, and professional and ut ilise all appliances which will reduce the men of high standing, volunteer for the front operating expenses. as freely as their less fortunate fellows and

The additional cost of such n1ust be examined, t he sacrifices thus made at the call or' con-and the interest and si11king fund on it compared science go far to justify the contention referred with the saving in operating expenses which they to. However that may be, there is no ques-effect. The engineer who has solely been used to tion that the mechanicul ar ts - and thus ulti-electric lighting plants, very often overlooks the mately the comforts and conveniences of modern question of labour-saving devices and economical civilisation-:in many cases owe their o1igin, and plant, because in his mind the cost of labour and much of their ~evelopment, to t he requirements of materials necessary for generating power is a very war. The nations generally have never failed to

sma as d ' . compare to the money expended on mate~al and labour necessary to keep the plant

runnmg .. In such stations it is, therefore, of the greatest tmportance to most carefully investigate

small part of the total cost of production. appreciate the truth of the old adage : There are three sources of power used for gene- "Thrice a.r!Ded is he who has his quarrel just

rating electrical energy on a commercial scale : But ten t1mes he who gets his blow in 'fust r_,, water -power , steam, gas. The former will not be The efforts of every t ribe and race have accord-dealt with at length in this series of articles a~ ingly .been directed towards the development of there is, unfortunately, but little such power a~ail- maten al whereby the planting of this first blow able i!l Gr~at Britain. The second is that generally may be most efficient ly effected.

m~ed In this country, alt hough there are authorities Probably th.e m~talworkers' art in the Middle who foretell that the gas engine is bound to replace Ages ; ea.ched Its h1ghest developmen t in the con -the steam engine, even in the brgest units. The struct10n of those beautiful suits of armour with

E N G I N E E R I N G. [ APRIL 6, I 900 .

12-POUNDER SEPARABLE I.JANDING GUN. CONSTRUCTED BY MESSRS. VICK.ERS, SONS, AND ~1AXIM, LIMITED, AT THEIR ERITH \YORKS, KENT.

(For Description, see P age 433.) Fi[j 60.

....

~ -- - -- - - -...-. -- - - - :~ - - - -

I

0)

.. "'(- - ... ---- ----... --..... -- ------ -------------------------------------..:.----- ------------------- ............... .. ----- ....... ------------ l .LengtJI./ uf' A tube 155 ... - .. - .. --- --t ---------------------------- -------- L enntll/ of' Jcu:l

12-POU NDER SEPARABLE LANDING GUN. CONSTRUCTED BY MESSR S . VICKERS, SONS, AND :MAXI:Nf, LIMITED, AT THEIR ERITI- WORKS , KENT.

(For D escription, see P age 433. )

FIGS. 74 AND 75. which t he medi[eval baron was won t to protect his precious person before sallying out to t he fi gh t. At t he presen t date, t he workmanship of range-finders, tangen t sights, and other military acces-sories, riv~ls in perfection t hat of the instruments forming the equipment of a modern astronomical obser vatory. I t has further to be obser ved t hat t he needs of obser vatories constitute but a small trade ; whilst military requirements are very much greater, and have a proportionately more marked effect on workshop practice.

In no depar tmen t has t his influence been more effectively displayed than in that of heavy forge work. I t is true, n ever theless, that Nasmyth's in-ven tion of the steam hammer had a p urely civilian source, a difficulty in forging t he shafting for on e of the early steamships leading to the suggestion of the new tool. At the same time, it has to be ob-served t hat the largest hammers subsequen tly erected were devised mainly wit h a view to dealing with heavy gun and armour forgings, and culmi-nated in that er ected, a decade ago, at t he South Bethleh em Iron Works, by Mr. J ohn Fritz. The t up in this instance weighed 125 tons, and had a strok e of 18ft., whilst t he anvil weighed 1400 tons. A hammer of practically equal power is that at t he works of M essrs. Marrel Freres at Rive-de-Gier. F ran ce, which has a t up weighing 100 tons, with a stroke

Q -h

,

V ICKERS' 1 2-P ouNDER Gu~ AND CARRIAG E IN PARTS Sui TABLE FOR TRAN~PORT BY l\fE~ OR 1\fu LES.

&:Ja

FIG. 73. GUN IN FIRI:NG Pos iTION ,

of 19.68 ft. I n E ngland the deYelopment of the steam hammer was checked by the early introduc-tion of the forging press, which is now used almost universally for heavy work , and is held to produce much sounder forgings. A hammer fa.ils to work the deeper - seated metal satisfactorily, it s effect being largely superficial. The press was invented by Sir J oseph Whitworth, owing, it is stated, to legal proceedings taken by a school in the imme-diate neighbourhood of his works, t he complaint arising from the vibration set up by his heavy steam hammers. N ot wishing to move his works, nor to buy out the school, the press was tr ied, and found far superior to the hamn1er. We understand, n evertheless, that Sir J oseph was far from grateful to the school in question- which was thus the real originator of the invention- but took an early opportunity of " getting square."

A very interesting review of t he growth and present posit ion of the armour-making industry has recently appeared in France, the a uthor of t he volume being l\L L. Bacle, ingenieur civil des mines, a gentleman who has certainly been a careful student of armour-plate manufacture and t rials.* To F rance belongs the honour of producing the first armour-clad. T his was the Gloire, a wooden

* "Les P laques de B lindage." Paris: Cb. Dunod.

-

::x> ~

~ .......

t-+ 0\

...

........

\0

8

l '

trl z ()

~

z trl trl ?::'

~

z ()

..p..

frigate of 5614 tons displacement, the keel of which was laid in 1858. The whole broadside of the vessel was protected, the armour consisting of plates of hammered iron 4 in. thick. The first English armour-clad was the Warrior, launched in 1861! the armour in this case being 4! in. thick ; and 1t was made by rolling, a substantial imp rove-m ent on the method of production adopted in the case of the Gloire. For long, simple wrought-iron armour h eld the fi eld ; but as the power of artillery increased, g reater and greater thickness of plating was required to stop the projectiles, culminating in the 24-in. side-armour of the Inflexible. M . Bacle states that the 55-centimetre armour of the Admiral Duperre is the thickest ever used ; but 55 centimetres is only 21.65 in., nearly 2. 5 in. less than that of the Inflexible.

Obviously there was, of necessity, a limit to th e growth in the thickness of armour-plate ; and, in fact, t he area protected, which in the earlier boats had been the whole broad ide, was in later con-structions of necessity reduced to the walls of a mere citadel amidships . Any attempt to afford so complete a protection as was obtained in the earlier ironclads would have led to t he use of dis-placements, such as t o make the ships quite un-nlanageable. Evidently, therefore, it became neces-sary to improve the quality of the armour, as, for the reasons given, a further increase in its thickness was impracticable. In France, where manufac-turers were quicker than in this country to appre-ciate the value of skilled scientific assistance, th e solution of the problem was sought in the adoption of steel, the lead in this direction having been taken by MM. Schneider et Cie., of Creusot. This advance did not meet with favour in this country, as few manufacturers even n owadays are pre-pared to pay other men to experiment for them. English steelmakers . when personally interested in scientific matters, will experiment for themselves, and have thus done mo t excellent work ; but such men are exceptional, an d consequently n one of our great firms have had the honour of pro-ducing such an array of skilled scientific metal-lurgists, as have issued from the laboratories of certain of the great French steel works, included in which we find the names of Messrs . Osmond, Le Chatalier, Charpy, and several others of almost equal prominence. L ooking from the factory, rather than from the laboratory, side of the ques tion, English firms produced compound armour with the idea which since proved so profitable to manufacturers, of breaking up the projectile against a hard face, backed by softer metal, the latter ser~ing to hold the hard but brittle front face together. This conception was certainly on the right lines, and is similar in principle to the "Harveyed" or " Krupped " plates now generally adopted.

Two plans of attaining the end sought were patented- the one by Mr. Wilson, of Messrs. Ce.mmell and Co. ; and the other by Mr. Ellis, of M essrs. J ohn Brown and Co. In each a front plate of steel was welded to a back plate of iron, t he processes differing in the details of effecting t his union. In the Wilson plan the iron backing was raised t o a r ed heat, and the steel plate cast 011 top of this ; whilst Mr. Ellis placed the steel front plate and th e iron backing at a suitable distance apart in a mould, and ran molten steel between the t wo. The union was then consolidated by rolling. The French rights for the Wilson patents were pur-chased by three French firms, and a sharp contest broke out b etween these and the Creusot Works, who made plates of homogeneous steeL At t he outset, M. BacM remarks, t he compound plates had the ad vantage, the steel plates often proving brittle ; but the manufacture of t he latter was gradually though ste.a~ily improve~ , ~ntil at the international competittOn at SpezZta 1n 1882, a Schneider plate 18.9 in. thick, proved rather better t han either of the competi ng compound plates sup-plied by Cam m ell and Brown. At competitions made a li ttle later at Ochta and at Gavre, the adnu1tage rested with the compound plates. At another com-petit ion at Spezzia, in 1~84, th~ steel pla.t~, however, proYed markedly supenor to Its competit-ors.; and this superiority was confirmed at the famous tnals at Annapolis in 1890, which practically s~tt)ed t he fate of compound armour. M. Bacle, 1t 1s true, asser ts that t he all-steel plates never proved superior t o compound plates of French manufac-ture, in which, he contends, greater care was .taken than elsewhere in inRuring the proper welding of the two metals; but this claim will doubtless not be

E N G I N E E R I N G. admitted by English and other steelmakera. It is interesting to note that M. Bacle claims t hat the French chilled-iron shells were better than those of English make, while some of our authorities have made the counter claim that British service chilled shell was better t han many French steel ones. The discrepancy, n o doubt, arises from the differ-ence in the test conditions of fire. The English authorities, deeming that the greatest fire effect is likely to be obtained with weapons of moderate calibre, h'lve arranged their trials from this point of view ; and the plate not being greatly over-matched, steel shells in many cases proved to be broken up quite as thoroughly as the service cast-iron ones. In France the contrary plan has been followed, the plate being generally greatly over-matched by the gun, and under these conditions Schneider all-steel plates proved superior to some of the earlier Harveyed plates, which were brittle and broke up. On the other hand, with a less dis-proportion between the gun and the plate, the Harveyed armour is known to be superior to the homogeneous plate, since the latter will be per-forated by projectiles which the hard face of t he former would break up. Which method of t rial is t he b etter, is doubtless a question of some difficulty ; but so fa r as r ecent naval experi-ence goes, it would seem t hat t he smaller calibre guns are responsible for by far the larger number of hits ; and whilst a big shell if it gets home may have app1lling d estructive eff~cts, the chances of a fair hit with such a. shell are decidedly small. The 8-13-in . guns of the Indiana and Oregon did not register a single hi t at Santiago, whilst t he 12 in. guns of the I owa and Texas, only hi t twice.

Whilst at the Annapolis trials the compound armour showed up badly, both in comparison with the plate of ordinary steel and that of nickel steel, which then made its fi rst appearance, the ad-vantage of the hard face in breaking up projec-t iles not too superior to the resisting powers of t he plate, were so evident that it became an object with inventors to endeavour to obtain t his desideratum in some way, which would not involve an uncer-tain weld between t wo dissimilar metals, a weak-ness recognised as the t rue source of failure in compound plates. M . Bacle, we gather, holds that French experience showed that a really good compound plate was still quite as good as the steel plate ; one of the htter, he states, similar to the nickel-steel plate tried at Annapolis, only got a second mention - " superieure H- when t ried at Gavre at a little later date.

The Harvey plate, in which the last objection to the use of non-homogeneous metal was removed, is, of course, of American origin, and made its delJ"Lt at Annapolis in 1891. The general features of this system of producing hard-faced armour are now well known, and are described in some detail by M. Ba.cle. The plate to be face-hardened is laid in a. furnace on a bed of sand, and its upper face, which is the one to be hardened, is covered with carbonaceous material, which for a lOi-in. plate is 8 in. thick. This is surmounted by a layer of sand 2 in. thick, and finally the whole is enclosed in firebrick, preventing access of air. The furnace is then started, and the tem-perature raised to about the melting point of cast iron, and maintained at this heat for about 120 hours in the case of a. lOt- in. plate. The whole is then allowed to cool slowly, the covering not being removed till the plate has sunk to a dark red. 'l'he plate is again heated for reforging, so as to correct any warping which may have arisen during the process of cementation ; and this done, it is reheated to a hardening temperature, and cooled hy the application of water to the cemented face. The snrface thus p roduced is unattackable by a cutting tool ; and this was at first t he cause of much difficul ty and trouble in making boltholes and the like, a difficulty finally got over by a modi ficat ion of Professor Thomson's system of elec-tric welding. In this case a current, amounting to some t housands of amperes, is passed between two water-cooled copper electrodes resting on the plate around the pot to be annealed, and which rapidly bring t he interYening metal to a bright red heat. The current is then gradually reduced, t hus allowing the heated spot to cool slowly, after which it can be drilled or cut in the usual manner. Whilst the process of cementation above described is that most generally adopted, Schneider and Kru pp employ gas cementation, ordinary illuminating gas being used as the vehicle to bring the carbon

[ APRIL 6, 1 9oo. into contact with the plate to be cemented.* More recently Krupp has, by a method still kept secret, managed to produce plates in which t he hard face .is combined with .an exception ally .tough backin~, The pr?cess IS supposed to consist of success1 ve tempermgs and annealings, effected at very carefully regulated temperatures the latter varying with the kind of steel used. Pro: bably these temperatures have a direct connection with the breaks in the cooling curve of steel to which so much attention has of late years been directed by Osmond, Hoberts-Austen, and others.

The conditions of test for armour-plates vary very much in different countries. Our own Government attack a sample plate with guns of moderate power, and if the result is satisfactory, all plates made by the same process which has proved satisfactory to the inspectors are passed for service. In America the authorities adopted the plan of calling on firms to make t he armour in batche.c:. The plate which appeared least satisfactory to the inspector was then selected for test, and the acception or r ejection of the whole batch was depen dent on the behaviour of this plate. It will be seen that enormous pecuniary interests were therefore involved in the success of the trial plate ; and this, it will be remembered, led to a gross scandal : it being found that in cer tain cases the plate after select ion was re-treated, in order to make sure of its acceptance. Owing to this fact the plate, instead of representing the worst of the batch as intended by the inspector, was at the date of trial probably superior to its fellows. The system pursued in France is somewhat similar, exposing manufacturers to ettual temptations; but we ha\'e not heard amongst them of any such lapses of virtue as referred to above. The English system is, n o doubt, t he cheapest in the first place; whether it will prove so under the test of war remains to be seen ; we are fain to hope that the ave1age of plats supplied unn er these conditions will be quite as good as those made by a more rigid system.

THE LANGE ~IO 0-RAIL U FENDED H.AIL WAY AT ELBERFELD-BAR~IEN.

(Continued from page 413) IN 1893 the municipalities of Elberfeld and

Barmen, which were then contemplating the int~o duction of an elevated electric railroad of the Sie-mens and Halske type, invited the expert opinion of three well-known railway engineers - Von Bor ries, Goering, Koepcke-on the Langen schem.e. The exper ts deciding in favour of a suspended rail-way, negotiations were entered into wit~ the Con-tinental Company for Electrical Enterpnse. These neO'otiations r elated to a t wo-rail t rack, but the sinbgle rail was soon agreed upon. In Figs. 1 and 2, on the opposite page, we illus~rate the plan of this line. The black sinuous hoe on wh1ch the kilometres and stations are marked, represents the closed loop round which the carriages ~lways ~ra~el in the same direction future extensiOns w1ll be built upon the same pl~n. The len~t~ ?f the li.ne, i.e., the distance between the term I m, IS 1~.3 kilo metres (8k miles), 10 kilometres (6.2 m~es) of which are above t he River Wupper, a tnbutary of the Rhine whose width varies between 20 and 35 metres (68, ft. to 115 ft. ). Barmen and Elber-feld are the sister towns of the very pretty but narrow vVupper Valley, which used to be re ferred to with the epithet of " pious." The clear wa.ter of the river which made t he Wupper bleachmg yards, and the white linen, famous, ma! h~ve helpe.d to sustain that reputation. At the beg~nmg ?f thiS cent ury neither town counted 20,000 mh.abtta.ntsd The n earness of the coalfields and iron mmes, a~ the development of textile and chemical in~ustnes - dye works being particularl.y to be mentwne~i. have brought the join~ popula.tron of the two mu~~O palitie~, which rem am separated, up .to 300, The line beCYins at the Barmen - Rtttersl~ausen station of the 0 tate Rail way, follows the ' \ upp~r Yalley throuCYh the ister towns, and leaves It aga~n in the suburb of Sonnborn to proceed al~ng t e hiah street of Vohwinkel. A number of side ex

o d 11 n the last ten: ions are contemplate , . esp~ci~ Y I d the ment ioned suburbs, to which, 1t 1s ~xpect~ ' has city people will flock when better ra.1l serVlC~ been provided. These extensions will be ordmary electric surfe\ce trams, however . The sharp

0est cu:ve

on the track proper has a radius of 9 me res

* See E NGINEERING, vol. lxv., page 489

THE LANGEN MONO-RAIL SUSPENDED RAILWAY AT ELBERFELD-BARMEN. F ig. 1 .

B

Fl1J .2 . ~~

fr-Ot1" d\1 ia~ (518 2 A)

(295 ft. ), but there is one of 30 metres radius close to the Vohwinkel terminus, and on the sidings we find curves of 8 metres (26ft.) radius. The maxi-mum gradient is 45 in 1000 (1 : 22). The actual speed is for the present fixed at 50 kilometres (31 miles) per hour. As this speed can be attained within 15 seconds, it will be possible to keep up an average speed of 33 kilometres (20.5 miles) per hour, includ-ing stoppages. We are assured that this will be as fast travelling as on the State Railway, although the latter, which is a slightly shorter line, has two stoppages, and the ~uspended line eighteen inter-mediate stations. We confess we do not under-stand the necessity for the slow speed of the St~te line, nor for the many stations on the Langen rail-road, about 0.4 mile apart . The public might be trained to be a little less exacting as to the near-ness of the stations.

The general construction of the Langen super-structure will be understood from Fjgs. 3 and 4 on page 440. As the permanent way proper, apart from the superstructure, forms one of the characteristic features of the Langen system, we will first refer to that, and afterwards describe the different ways in which it can be supported. The permanent way, if we may use that term, is the invention of Director Rieppel, of the Mas-chinenbau- Gesellschaft, Nuremberg. It may be styled a double T -girder, and is illustrated in diagram in Figs. 5, 6, and 7, above, and further in Figs. 8, 9, and 10, page 441. All vertical forces

e

8 ...

~

I I

Fig.5. c ")>.. Q/ ;, (k

- :a~

~--.A#--------

SIIJ N,

4 O.TJll. -- ..

--.,.

l r

10() c Hor1.1~

.. ._ . . . . . . .. . .

UJoom !l!!!a . . ' ' ~ - - -- -

10D o Verticalt 'JDDm

J~ ,!

.P"o~ ~~

~ r ~ ,~ fr(JffV

- ~ .ffrg.6. ~

Q/ c e ""'"G.I 7f4~

Fig. 7. a-'= #;!~ $.-cl/

---A . OmdL ______ '\\. _+J

erfb ~.... ~~f ---------- ------~ ~-----'. 0 11ll------~-----~

e ftt' '~' ~ f' are taken up by the girder a b, which rests to allow of an inspection of the line. In the streets on bearings 10 ft. apart, and is stiffened against boards cover half the width, 4 metres (13 ft. ), of

l~teral and tor~ional strains by the horizont.,al the permanent way. As the dripping of the rain girders c d and e f . The upper member of the from the high structure could not have been girder a b is divided into the two halves c and d, avoided in any case, this arrangement is probably which are also booms of the horizontal girder c d. as good as any; such minor details may, however, The lower member b of the girder ab is not sub- lead to a little friction. divided. The booms of the lower horizontal The A-frames which support the permanent way, girder e f are formed by the rail bearers e and f . I consist of inclined struts andaconnecting yoke; they The vertical forces at e and f are transferl'ed to are a speciality of the United Engine Works Augs-the girder ('f, b by means of the ties a e and burg and Nuremberg. The fine bridge, opened in a f . On curves the main vertical girder ('f, b and 1897, which crosses the Wupper Valley at l\1iings-the upper horizontal girder c d are continued ten, some miles above Elberfeld, in one arch of in rectilinear paths, as we see in Figs. 8 and 560ft. span and 350ft. rise, was designed and built 12 ; only the rail bearers e and f, and the by the already-mentioned Director Rieppel. wind bracing between them are influenced by As the width of the Wupper River varies con-the curvature. This is constructively a very im- siderably, and as the flood-water sometimes rises portant po1nt, and makes the structure more uni- above the river walls, some of the struts have form and perspectively clearer. The permanent way their foundations in concrete, embedded in the need not be covered in, since there are neither solid ground (Fig. 4). Some of the struts are coals, cinders, nor water to drop or drip from any immersed 7 ft. into the river at high water. The engine. Above the river the track has been left consecutive frames being 30 yards apart, the quite free, apart from an occasional board put down current is not appreciably obstructed by these

~/

~~~-CI.i d'IS' I~ ~ ~ .;q

inclined posts; there is, moreover, no shipping on the Wupper, so that the narrowing of the river profile is not of consequence.

The portal frames, illustrated in Fig. 9, are in use in the suburbs of Sonnborn and Vohwinkel, where it was desired to keep the road unobstructed. The supports have, therefore, been placed near the kerbs of the sidewalk, where they do not occupy more space t han the street-lamp posts, which they are, in fact, replacing. Electric wires can be attached to these frames. In the avenues the rail track and carriages are more or less hidden by the foliage and branches of the trees. The third form of support, the central single post. indicated in Fig. 13, will not be wanted at Elberfeld. In architectural and resthetic respects it would be the most pleasing structure, especially in squares and wide streets. If there are no particular construc-tive difficulties to be faced, we may look forward to seeing these supports adopted in some other locality. In all three forms of support we have to distinguish between fixed yokes, which may be likened to bridges, and intermediate oscillating frames resting in ball-and-socket bearings. Figs. 8 to 10 show the two styles. The fixed yokes are placed at intervals of 200 or 300 yards ; half-way between them is an expansion joint; the intermediate frames can yield to temperature effects in either direction, whilst the fixed frames take up the longitudinal thrust.

(To be continued.)

~ '"d :::tl -t"'

~ -

-\0 0 0

I I

t'I1 z C) .......

z tT1 t'I1

~ .......

z G)

~ w \()

440 E N G I N E E R I N G. [ APRIL 6, I 900.

THE LANGEN MONO-RAIL SUSPENDED RAILWAY AT ELBERFELD-BARMEN. (For Description, see Page 438.)

,

Fro. 3 .

-

Fw. 4.

I

S ti:!L.

,J)

'

Fi '"'d

~ -t'-1 0\ -

......

\0

8 11 L 0 _l

tT1 z ()

~

z tT1 tT1

~ ~

z ()

~ ~ ......

THE JAPANESE BATrLESHIP "ASA.HI." W E begin this week the publication of the plans o f

the battleship Asahi, built for tbe Imperia l J a.pa nese Navy, by Messrs. John Brown and Co., Limited, at their Clydebank establishment, and t hese, we have no d oubt, will lend interest to the paper read be fore the Institution of Naval Architects, by Admiral Fitz-Gerald, on the J apd.nese Navy, and reproduced on p age 461 , especially as the Asahi is the larges t o f ba.Ltleships afloat. We d efer our full d escrip tion, Lut m ay give some general p articulars, with the results of the speed trials which termin ated last week. The principal dimensions are as follow :

L ength between perpendiculars . .. 400 ft. 0 in. , over all... . . . . . . . .. 425 , 6 ,

B rea1th, extreme . . . ... . .. 75 , 2i , Depth, moulded . . . . . . .. . 43 , , 7 ~ , Normal mean draught of water ... 27 , 3 , Displacement ... . .. . .. . .. 15,2u0 tons Indtcated horse-power . .. . . . 15,000

Four 12 in. guns of the most moder n type are mouuted in pairs in two barbettes, one forward a nd the other aft, on the midd le line of the vessel , each p air commanding an uninterrup ted arc of training of 240 d eg. The manipulation of the machinery and all the operations of loading and laying tbe guns are per-formed by hydraulic p ower ; the loading can be p er-formtd with the guns in any p osition of training. The guns and g unners are well shel tered by means vf heavy armoured shields, which r evolve with the turntables. The secondary a rmament consists of fourteen 6-in. quick-firing guns, each mounted in a separate c!lse-mate; twenty 12-p ounder, eight 3-p ounder, a nd four 2~-pounder quick-firing guns, with four submerged torpedo tubes in two compartments, one forward and one aft.

Great care h as been bestowed upon the arrangement of t he protective material. There is a main belt exteodiog for a length of 250 ft. amidships, the total d epth of this belt being 8 ft. 2 in. , and it is intended that when the ship is floating at the n ormal water line the lower edge of the armour wi1l be 5 ft. 6 in. below water , and the upper edge 2 ft. 8 in. above water. The maximum thicknees of t his btlt is 9 in. The central cit:tdel of a rmour is completed by traosver ses or bulkheads extending obliquely across the ship a nd enclosing the bases of t he barbettes which protect the p osit ions for the heavy guns. Forward and aft of t his main belt the protection of t he water-l ine region of the ship is completed by a rmour carried to the bow and stern . Above the main belt the sides from lower to main d eck are covered with armour o f a thickness of 6 in. ; this belt extends for a leogth of 250 ft. , a nd is completed by oblique t ran sverses at the e nds as described for the main bel t. Armoured doors are fitted in these transverses for affording con venient means of communication a long the deck when in port. The protection of the vitals of t he ship is r endered the more secure by a heavy protective deck extending all fore and a ft, and t;loping away from the underside of t he main armour bel t. The protection to the armament is arranged in a very thorough manner. For the 12-in. guns at the extremities circular barbettes rise from the protecti ve deck to a h eight of 22 ft . 4 in. above the n ormal water line ; these barbettes are plated with armour of a maximum thickness of 14 in. Each 6-in. quick -firing gun is enclo~ed in a. caeemate with a.n a rmoured front 6 in. thick . The forwa rd conning-tower is comp osed of 14-io. armour, and the after tower of 3-in. armour. The w hole of the armour -plating was manufacturecl by 1\[essrs. John Brown and Co., Limited, Sheffield, and is of the highest quality procur-a ble, every plate having been treated by the impro,ed H arveyed nickel-steel p rocess, except those for the conning tower, where experience shows t hat t he curva-ture of t he platee is too great to enable this process to be successfully e mployed ; these plates are conse-q uent ly made of ordinary Harveyed steel. A s a pro-tection agains t attacks from torpedoes, a broadside net d efence is fitted for a length of about 300 ft. a mid-ships; the nets are supported by steel booms, and whe n not in use s t ow on a convenient shelf worked round the side:~.

The ship is propelled by two sets of three-cylinder triple-expansion engines. Each of the two sets is de-

~igoed to develop 7500 indicated h orse-power, giving a combined indicated power of 15,000. Steam is s up-plied by 18 water-tube boilers of the Belleville econo-miser type, working at a pressure of 300 lb., which is reduced at the engines to 250 lb. The d iameters of the high-pres mre Cj linders are 32! in. , of the inter-m ediate-!- reJsure cylinders 52 in., a nd of t he low-pres-sure cylinders 85 in ., all having a s troke of 4 ft.

The vessel lefc Portsmouth H a rbour on Tuesnay, March 20, and after compasses had been adjusted, a few low-speed runs on the measured mile at 1 1 tokes Bay were made wi"h the following resu l ~s : ~lean speed, 6.69 knots, indicated h orse-power, 6 L3; speed, 9.28 knots, indicated horse-power, 1610 ; and for a speed of 13.06 knots the indicated horse-power was 4355. On Wednesday, the 2 1st ult., t he vessel ran her coal consumption trial with the r esult that at 12,947

E N G I N E E R I N G. indicated horse-p ower t he consumption only averaged 1.59 l b. per indicated horse-power per hour. The con-tract stipulated that this t ria l should t~ke place with a development of p ower of at least 12,200 horses, so tha t with the high p ower developed the low coal con -sumption is a ll the more creditable. But for the fact that the wind and sea w ere both too high, a sp eed trial at this power would have been made over a 12-knot course between tart Point and Berry Head. From the records taken, however, it appeared certain that t he speed at this p ower may b e fairly taken to be about 17! knots.

The full- s peed trials took place on the 23rd ult. , on the selected d eep-water course between B erry Hea d and tart P oint, a distan ce of 12 25 linots. Four runs were made in alternate directions , the firs t and third b eing in the teeth of a north-easterly gale. Notwith-s tanding this, the mean sp eed realised was 18.3 knots. The sp eeds on the four runs were as follow : First run, 17.92 knots; second run, 18.08 kt1ots ; third r nn , 18.65 knots ; and the last, 18.30 knots, the mean of means being 18.30 knot3, as before s tated, wi t h a m ean indi-cated horse-power of s lightly over 16,000. After the full-speed tr1a l, circles were made to port and star -board with each steam -st eering engine, the vessel meanwhile being at full speed. Manc.euvring wit h the hand-steeJ ing wheel s was also su ccessfully car r ied out at a speed of 15 knots. The u sual stopping, starting, and reYc rsiog trials wer e made on the return voyage to 1 pithead, the return p1ssa.ge being made at a speed of 17 knots. The J a. panese Governm ent is to be congratulated on this latest addttion to its fleet.. The trials just concluded pro\e the Asahi to be as fa-,t a s any battleships a pproaching her in size, while wi t h he r large displacement it is obvious that the offdns ive and defensive qualities of the ship are u::1e:xcelled.

THE ROLLING OF SHIPS ON W A YES. A n Experhncntal llfethod of A scertaining the R olling

of .Ships on Waves.* By Captain G. Ru so, Naval Architect Royal Italian

Navy; Member. 1. THE paper which I have the honour of submi tting to

the meeting, though relating to a new application is doubly connected with subjects which have had the largest development before this Institution, and which now have a literature more ample than any other bra nch of naval architecture.

First, I intend to refer to the classical theory of wave motion and of the rolling of ships on waves. the bases of which were established by the late lHr. W. Froude, and confirmed by the researches of more recent in vesti-gators, whose names need not be repeated here; and it is on the sam~ bases that my researches have been founded.

Secondly, I intend to refer to the well-known theory of mechanic .t.l similitude; which, in other branche~ of na va l architecture, has ltd us to the direct solution of the im-portant problems of resistance to motion, efficiency of propellers, oscillations in still water. and to which I have once more recurred for the mean~ employed in my method for ascer tainins-, by mechanical experiments, the rolling of any given shtp on any given series of waves.

And now, supported by this two-fold consideration, I will endeavour to submit to the examination and discus-sion of the Institution a paper relating to my method and the results which I have been able to arrive at.

2. In e xperiments concerning still-.water oscillations of ships (as well as in those rela ting to the resistance to n:.otion , or to the efficiency of ptopellers in connection with a giYen ship) a model and a tank are required, re-

pre~enting on a small scale the ship and the waters in which she oscillates. W ere it possible to produce in the t ank regular, continuous, and .well-proportioned waves, s uch a method would enable us to solve the problem of the rolling on waves. Nothing den otes that something of this kind will not be attained in future ; but for the present we are still handicapped by unsurmounted diffi-culties.

These difficulties do nob present themselves in the method I have s tudied, where a ship, rather than by a model, is represented by a pendulr-.r body of a special form, which for brevity I have called a "navipendulum , ; and where the wave motion of water, rather than by real liquid waves, is represented by a ~pecially contrived apparatus. My navipeodulums are therefore made in such a way as to possess all the geometrical and mecha-nical properties which are in play in thP. transversal

o~cillation of ship~, so that a ship having a given form of bull, a certain disposition of weights, and certain given qualities of still wate r ex1.ioction of oscillations, &c., can be represented by A: corresponding: navipen~ulum. L ike-wise, my wave-motton apparatus lS made m such a way as to exert on a navipendulum the same action as the waves prodnce on the corresponding ship.

I have divided this paper into three parts : the first par t relates to the principles for the composition of oavi-pendulumR; the second relates to my wave-motion appa-ratus : and finally, the third concerns the method of experiments and some results of trials made during the shor t time I have bad at my disposa l since the com-pletion of my apparatu~, which wa.s constructed by order of the Ministry of the Royal Italian Navy.

I .-CoMPosnroN o~ N A , rp ~o;NnULU MI:$ . 3. The point of de parture of my method for compos-

ing a n avipendulum is the principle that a ship floating

*Paper read before the Institution of Naval .Architects.

[ APRIL 6, 1900. in an ~prigh~ or incl~ned p osition may be compared, from a stat1cal pomt of v1ew, to a supported body. su that this body b~ the ship herself, freed froU: th~~~i~: of the S';Irro_undmg water, and that the geometrical sur-face, whw~ lS th~ loc.us o_f the centres of buoyancy for all the conce1 vable m clmattons, should become a mate 1 surface, thr~ugh which the srup stands upon a. horizo~~l plane or bas1s.

If only transverse inclinations are considered as is now the case, then the su~fa~ of the centres of buoyancy may be r~placed .by a cyhndncal surface, having for its cross. sect~on the hoe of . the centres of buoyancy in a transverse sect10n of the sh tp. In so doing, we suppose-as is

co~monly assumed-tha~ the ce~t~e of buoyancy, as tbo sh1p heels from the upr1gh~ pos1t10n, a.hvays remains in a p~a.ne tran~verse t_o t~e shtp {plane of inclination).

~ ow, bes1des thts hoe and the corresponding cylin-drical surface, t~ere are. an i_nfinite number of other lines a nd correspoodmg cyhndrlCa..l surfaces which equally p ossess t?e property _o f exciting, when r~ndered material and restmg on a honzontal plane, a reaction of the same

yal~e a~d line ~f. action as the bu(Jyancy at any angle of 1~chnatlon. Evtdently such a property belongs to any hne parallel to the curve of the centres of buoyancy or having the same evolute-the metacentric evolute pr~per of the ship-at the d isplacP.ment considered.

4. Among the infinite number of lines which may be drawn parallel to the line of the centres of buoyancy (see Fig. 8, pag~ 445), p_referen~e sho~ld be given, for our pur. p ose, t o a hne havmg all Its pomts as near to the centre of gravity as possible. Naturally it is not a rigorous con-dition to ful fi l ; it is advantageous to approximate to it as much as possible, and this may be done without difficulty.

Fig~. 9 tc, 13, page 445, show for some war and merchant ships the curves which have been judged well adapted for our purposes. They relate to ships of different types and sizes. By t hede examples a concrete idea is given about the form of these lines and their extension, in com. parison with the dimensions of the corresponding midsbip sections.

It is easy to understand that these curvee, in their central parts (for angles of inclination between the upright and 10 deg. or 12 deg. ), are circumferentjal arcs, bavmg their centres in the points M. Moreover, we observe that the tracing of the metacentric evolutes, and conse-quently of our desired curves, can be performed very en.sily, starting from the ordinary curves of stability (curves of the arms of the righting couple).

5. The statements made above concerning the st&tical s tability may be equally extended to the dynamical stability; there is a perfect correspondence between the case of the floating ship and that of the supported ship. To bring the ship from the upright to any inclined posi-tion, an equal quantity of mechanical work is required in both cases.

6. Reverting to the dynamical conditions of the roll_iog in still water, and considering, fi rst, the hypothettcal case of uoresisted rolling, it can be ~asily seen t?a.t t~e rolling motion of the supported ship, as descnbed ~n paragraph 4- apart from the resista~ce ?f the s~rface~ m contact, from air resistance, and takmg Into constderatlOn t he angles of inclination 8 = f (t) (not the path of_ the cen tre of gravity)- is practically equal to the unrestSted rolling of the floating ship. . .

We ~ay practically equal, and not tdenttca.l, on account of two factors, the influence of which we neglect,

V1 z. : . (et) First, the influence of the distances of _the mst&n

taneous axis of rotation of the supported shtp fro!D the longitudinal axis passing through thecentr~ of .gra.Vlt~

{b) A nd, secondly, the influence of th~ d1ppms os~tllations accompanying the transverse uoreststed oEctllattOnS.

The influence of the factor a app~rs very small, con sidering the na t ure of the curves mentiOned .10 paragraph 4 (see Figs. 9 to 13, page 445). It can be ven 6~d that, .ne cording to the curves which we ha~e chosP~ tn practiCe, the distance of t he instantaneous ax1s of rolhng _from t~e centre of gra\"ity never produces an augmentation of Tou in the moment of iner tia, and, consequently, tb~ Pfrtod can never be altered by rtif ~f i ts va~ue as resultmg rom the theoretical ca-se of unreststed rollmg.

The influence of the factor b may al'3o be neglec~ed, or, better, it may be a.ssu.med that . th~ volu_me of diSp~a:i mentis invariable while t he shtp IS rolh~g. A ge e demonstra tion of this subject cannot be gtven; ~ow~r~r, by recurring to an experi~eotal process, rc;tentiOne 1~ Appendix I ., some conclusiOns may be. a.rr1ved at ~~ cerning the smallness of the errors r~sultmg from neg ing the vertical oscillations of the shtp. t f

7. 03cillatory motions by rolled surfaces canno ' ~ course, be produced for effective shi~, generally spea

mg. Id ve the vVere it possible, such exper1ments wou ~ l

period of oscillation, not o~lY. for ~mal~ but alsof f~ll ~b~~ amplitudes of rolling. ThiS IS a c~nsequence 0b riod has been said before. Now the m crease of t e pe with the magnitude of oscillations maye~ert, as w~ .know, a considerable influence on the behaviOur of s tps on wave$. .._.J f om

A lthough for practical reasons, we are preve~~ dr.ffi ' . k ' d th lS DO 1 proceeding to experiments of th1s 1n ' .ere h L

culty in doing it on !l' red_uc~~ scale, applymg t e genera principle of mechamcal s1mihtude_. be

The law of similitude, as apphed to our case, may expressed in the followi~g terms: 445) fit to oscil.l&te by

L et us have a body {Ftg. 14, page . 1 surface rolling upon a plane ~y ~ea~s ?f a cyhodn~ b draw~ the cross-section of whtch JS similar to the eh 't of for a given ship, parallel to the curve fof t ~t~? le~the buoyancy and p~ssing near the centre o gravt h body ratio of similitude, arb~tra~ily fixed, be;; let su~ry aof the have its centre of grav1t~ m the plane ... oHsfmm~he central cy lindricaJ surface at a dl.Stance d = " rom

APRIL 6, 1900.] ww a a w

E N G I N E E R I N G. t . h 1. H being the corresponding distance.for the ances (which result, as is known, in a disp!a.cement o~ the et~atg t methe wei ht of this body be p. D, D ~et~g- the axis of rotation in comparison with the axts of unreststed s~tp. Let t f tbe;hip and p. a certain ra tio of s1mthtude rolling in an altera tion in the period, a nd in a. .gradual dtSJ?laceienfi~ed . let its moment of inertia about ~be f xtinction of the motion), we are led to the followmg con-arbt~ran.Y 1 axis' a-ssing through its centre of gravtty olusions : longi~~d1ma I bei~g the corresponding element for the (a) With regard to t he still-water period being length-be P." 0 , 0 ened on account of the fact that the i nstantaneous axes of shiP: d tion~ the oscillations of a body com- rolling do not . coincide with the a~ is passing through the

G1ven these con 1 ' which constitutes my navipen- centre of gravity, and that a certam mass of water, sur-posed in ~u: a. mil:rn:~, the oscillations of the ship, and rounding the ship, is carri~d by friction9;l a~d _di_reot resist-dulum, w~l s~~- will be verified between the dif- ance in the rotatory mot10n of the shtp, I t ts m no way the followmg re a I~ns a be com

444

"'

J

tSJH.}

.FiJ. 7.

APPARATUS

I \ I \ \ I

\ ' ' \ \ \

' ' I \ ' \

FOR

Fig.5.

S'

\ \

0' \ ,\ t \ \ \ ' '

Table I. will pass between the various elements of the real wave motion and the corresponding elements of the motion impressed on the plate of the apparatus.

14. The wave motion to which Fig. 14, page 445, relates may be produced on a moderate scale by means of the apparatus which is described in Appendix II., and which is shown by Figs. 5 to 7, annexed, and by the photographs (Figs. 1 to 4, page 448). Here I will confine myself to men-tioning some of the principal features of the apparatus.

First of all, with reference to Fig. 14, the conditions of a movement similar to that of the plate a b are un-changed, if the normal MP, instead of passing through the point P (which may be at a great distance), constantly passes through a. point M1 (Fig. 15, page 445) at the end of a radius 0 1 M 11 supposing this radius to turn with a uniform speed, always in a direction parallel to the radius 0 M, about a. certain point 0 11 on the vertical of the

E N G I N E E R I N G.

EXPERIMENTS ON THE

[ APRIL 6, 1900.

ROLLI NG OF SHIPS .

Pig.6. A ~ "

. .

~

' ' 1..

-- - --

,--------- ----------, : I I I I I "-- -------- - -------.I

I ' I ' ,, ,,

I : ' .

-- ---

H

I :

~u.c .

point 0; it is only necessary that the length 11 of the radius 0 1 M1 and the distance 0 0 1 = k between the two

centres be so proportioned thatr1 = r "AR-k. "A.R

The practical disposition adopted corresponds to that indicated by Fig. 5. The essential pa.rb of the appa-ratus (Figs. 5 to 7) is the plate L, on which the navipen-

dul~m rolls. ~~is plate, instead of remaining at rest in a. hor1zontal pos1t10n, as we supposed when the na.vipen

dulu~ w~s described! is made to take a motion equal to that md1cated by F1g. 15. The rod k (Fig. 5) repre-sents materially the normal to the plate, and acts as a governing lever to regulate the inclinations of t he plate L. Means are provided for arranging the appa ratus at the required values ad the radii r 11 (Fig. 0 an-nex~d). ~esides the plate ~ and the organs necessary for 1ts mot10n, the appara.t1;1s mclu~es a regist~ring appa-ratus, an electro-motor w1th speCially contnved resist ances, a regulator of speed, &c.

The register.ing apparatus is . carried on the same pin (C) ar~mn? wbtch the centra~ ax1s of the plate L oscillates On ~h18 pm a small board ~ 1s arranged, which during the mot10n of the apparatus-while following the plate L in the rotatory motion-is maintained constantly hor1zont~t1. In fact, the plate z is connected to the rod j , which is made so as to remain constantly vertical Ly a disJlosition which clearly results from an inspection of the Figs. 5 and u.

---

A

. ... .

. . ''" : ' .. ~-- I !I - - - - - .... -------~ _________ ... __ .J ... l __

It should only be remarked, for a. clearer understanding of the figures, that the radius r 2 (Fig. 6) should be, a.s de signed in the figure, always = r. The registering appa ~atus gives, on a sheeb of paper, a diagram. of the ~ype Illustrated later on. Such a diagram contams five lines, viz., a toothed line constituting a. scale of times i~ Eeconds; a sinuous line, which is cros.'!ed by a recti

TABLE I.

Elements to Compare.

Length of the wave .. Height . . .. ..

Radius of the rolling circle . . . . , orbital oircumferencel

Period (time of revolution) . . . . Weight .. . . .. .. . . Centrifugal force Apparen t weig-ht

Angle of inclination of the virtual upright to the true vertical ..

L H R r

T w c W'

9'

i\L X i\H X XR i\ i\1' i\

AI 'A T 1\ p. W p. )1.0 jJ.

JJ. W' jJ.

9' 1

linear line, and which gives, instant by instant, the amplitudes of the rolling of the na.vipendulum rela ti vely to the vertical ; and a sinuous line, crossed also ?Y a rectilinear line, and giving, instant by insta.~t, the ID clinations of the normal of the wave to the vertical.

In Appendix II. further details are given about the arrangement of the apparatus.

(To be continued.)

BELGIAN COAL EXPORTS.-The exports of coal from Belgium in the first two months of this year were 773,~03 tons, as compared with 686,451 tons in the corres_pQFnding period of 1899. In these totals the exports to ranee figured for 566,375 tons and 474,390 tons respectively.

ARGENTINE RAILWAYS. -The length of ra.il~ay jn the Argentine Republic at the close of last year ~ returnehd at 16,114 miles, as compared with 15,802 miles at t e close of 1898, 14,931 miles at the close. of 1897, 14,536 miles a.b the close of 1896, and 14,311 m~es a~ the o~:d of 1895. The capital invested in Argentme railways increased at the close of 1809 to 1,240,424,297 d{lsi89~ compared with 462,730,642 dols. at the close o . i The average return obtained last year upon the ca.ptta expended was 3.11 per cent.

AP P ARAT U S FOR EXPERIMENTS ON THE ROLLING OF S H IlP S . - .. >-

Fi-9-8: r--___ !+ 6-.J

... I

I l ~ -J.--1:-.:::..a -o-. ~~-~~--

Fi1) . 70.

F0 .!J.

I

I I

F~ .11.

I

(For D eacription, su P age 442.)

...

I

I

I

I I

I I I I

R1J.14 . #

8

.Fig. IS

--------

I

I I

I I

'/~6 . ' . // : / -J. ~ -~ .. /; . . / ,. I I

I . . I ,

I '

I / /1 / 1 I o I

' ' l I

L . .. I ,... .

'"0 ~ ""'1 t'-4 0\

...

~ \0

8

l '

t' ~ W..Wd~;$/&/7/~ 1::11 - .__ 11:J '\,. '\.. \.... "'\..f::-.Jt" >

NOTES FROM THE NORTH. . GLASGOW, Wednesday. Gla~g~ Ptg-lron Market.-At the forenoon m eeting of

the ptg-uon warrant market on Thursday about 20 000 tons :were dea.lb in. The feeling was very good from' the openmg, and at the close Scotch iron showed another ,.ain of 2~d. per ton. The market was easier in the after-noon, and prices bad a sharp reaction. Scotch closed

8~d. ~ow~ from the forenoon, Cleveland 1~ ., and hemat1te uon 5d. p er ton. The sales amounted to

~5, 000 tons, and the settlement prices were: Scotuh u on 74s. per ton, Cleveland 76s., Cumbetland and Mid-

dle~brough hematite iron 82:J. l~d. and 84s. per ton. On Fr1day forenoon some 20,000 tons were dealt in. At first the ~one was firm, but on a. few lots being freely offered pr1ces receded. There was a. general drop of 2d. to 3d . p er ton. The market was firm in the afternoon Scotch recovering the forenoon drop, and the sale~ amounted to 8000 tons. The settlement prices were : 74s., 75s. !ld., 82s., and 84s. 6d. per ton. About 15,000 ton~ of iron were dealt in on Monday fore noon. Pnces were strong. Scotch rising lO~d. per ton, Cleveland l s . . 1d., and hematite iron ll~d . per ton. No transactions, however, were reported in Cleveland iron. In the afternoon the market was very strong; Scotch closing ls. 3d. per ton on the day Clev:ela.nd l s. 4d., and bematite iron I s. ld. per ton: BuElm ess was confined to Scotch and hemati te iron and 15,000 tons cha!lged hands, the settlement prices b~ing: 75s .. 3d., 76s. 10~., 83~., and 8-ts. 6d. per ton. A p oor busmess was done on the pig-iron market on Tuesday forenoon. Only 10,000 tons changed hands. Scotch war-rants were d on e up to 75s. 9d. cash per ton, which is the

r~cord pri.ce for a great many years. L ast year the b1gbest prtce was 75s. 7d. per ton cash, and we have to go. as far back as 1874 to get a better price than was pa1d on Tuesday forenoon. In tha.b year the highest figure was as high as lOSs. 6d. cash per ton. From the besb price on Tuesday forenoon Scotch reacted to 753. 4~d. per ton, which left the n et gain from 1-Ionday at 2~d. per ton. Cleveland made 3d., and hematite iron the same amount. ~n the a fternoon the market was very firm, Scotch markmg another 1~. per ton and hematite

ir~n 1d., the sales being only 5000 tons. The settlement pnces were: 75s. 6d., 77s. ~. 833. 4~d., and 8ts. 6d. per ton. Business was quiet this forenoon, some 15 000 tons changing hands. Scotch iron made anothe r ~ecord at 76s. per ton cash, from which therA was a break to 75s. 10~d. About 10,000 tons were dealt in in the afternoon, and the tone was s trong. Sco~ch closed 6d. per ton up on the day, and hematite iron 7d. The settlement pri~es were : 76s., 77s. 4! d, 84.s., and 84s. 6d. per ton. The following are the shipments of pig iron for las t week from Scotch ports : For South America, 100 tons; for India, 100 tons ; for Australia, 314 tons; for Italy, '255 tons; for Germany, 2LO tons ; for H olland, 300 tons; for B~lgium, 700 t

APRIL 6, I 900] E N G I N E E R I N G. Manufactltred Iron and Stee~.-These bra~ches of trade

tinue very active, and pnces are movmg upwards. ~mmon iron bars .have been advan~d to 91. 10s., best ha to 101 while tron n.nd steel ship-angles and s teel b :rs lates'' are firm at l . Gs., iron ship-plates fully ~ ~~~~ Gd., and heavy sections of s.teel rails 7l. 103.-:&11 le~s the customary 2! per cent. dtsoount, except rails, which are net at works.

MISCELLANEA. TnE traffic receipts for the week ending March 25,

on 33 of the principal lines of the U nited Kingdnm. amounted to 1,695,957!., which was earned on 19,865~ miles. For the corresponding week in 1899 the receipts of the same lines amounted to 1,636,10Gl., with 19,604! miles O{>en. There was thus an increase of 95,85Ll. in the rece1pts, and an increase of 26li in the mileage. Messrs Bell B1othe1s, Ltd .-At the first annual meet-

. g of sh~reholders of Iv!essrs. Bell Brothers, Limited, Sir Lowthian Bell, Bart., who presided,, mov~d t he adoption f the report and bAJance-sheet, and ID domg so remmded ~he shareholders that they haVerage rate for freight does not excaed ~d. p er milE'.

The country meeting of the Surveyors' Institution, 1900, will be held, by kind permission of the L ord Mayor and Corporation of L eeds, i n the council cbam ber of the Town Hall, Leeds, on W ednesday, April 25, at 11 a.m. , when the following papers will be read and discussed : (1) 11 L eeds, i ts Past and Present," by Mr. John Hepper (Fellow); (2) "Nuisances and Noxious TradE*~," by Mr. Arnold Statha.m " (Associate); (3) "Covered S heds for Farmyard Purpose~," by Mr. A. T. W a.lmisley (Fe11ow) ; (4} A djourned discussion on the paper read by Mr. J . H. Sa.bin (Professional Associate) at the last meeting, en-titled 11 The Incidence of Imperial and L ocal Taxation on Rateable Property." The members will dine together a t the Hotel Metrop61e, King-street L eeds, on t he evening of April 25, at 6.30 for 7 p.m. Dinner tickets (one guinea. each, including wine) can be obtained from Mr. C. H. G?tt, 8, Charles-street, Bradford. The following da.y wlll be devoted to excursions to: (1) Places of interesb in L eeds and its vicinity ; (2) Bramham Park and Temple Newsam; (3) Y ork ; (4) Sheffield.

A ve_ry ingenious screw-cutting tool is described in a recenb tssue of the Iron Age. Every one know.:~ how diffi-cult it is for a~ inexperienced hand t~ properly regulate the depth of h1s feed ab each successive traverse of his tool in cutting the thread. At the outset a fairly deep out may be taken, but this must be deor6nsed as th~ work proceeds, or a torn thread is likely to result. With the tool in question, the proper feed is see;ured a.utomatica.lJy so th!lt perfect threads can, it is clai~d, be produced by unsktlled labour. The cutter consis ts of a steel disc ~hioh h!-'8 arranged round its edge a. number of out: tmg pomts, or teeth. The firsb traverse is made with No. 1 point. The disc is then rotated and the eecond out taken with No. 2 point, and so on. the ou~ ta~en with t he last poi?t finishi~g t he work. Eaoh pomt IS. ground so that m followmg i ts. predecessor It takes JUSt the proper depth of out, nothmg being le ft to the j udgment of thA workman. I t is found that a. standard thread, eight to the inch, can, with this tool be be out on a 1-in. steel ba.r in te~ traverses, running ' the Ja~he at a. speed of 135 revolutiOns p er minute. The Rrvett-Dook Company, of F a.n&uil, Boston, U. S. A., are the makers of the device. R Ed n reat Western Railway of Ireland and Mr. P~llardwa1 Cusack be~n appointed his successo;.-Mr. T .

info ' 0 248b Wellmgton-road, Eccles, Manchester, for [bs,?s tha.t e has been appointed sole English agent n Gee B~rgtsche Metallwa.arenfabrik of Kupferdreb " 1 nnany. , ,

'

A: repor t CJf the America~ Railway E ngineering a.nd MaiDtena.nce of Way Assomation asserts that the best steel rails produced in America. were rolled in 1880 rails of ~ore recen~ date being l.e~ satisfactory, though of' more umform ohem10al compos1t10n. It is suggested that the

447 reason for the decrease in wearing qualibies is to be ~ound in the higher temperature at which rails are now finiShed. The present practice in American mills is to rely solely on analysis for p roducing the pig, ores too high in phosphorus being mixed with those of better quality. The furnaces are driven at a high rate of produo~io? T he m~ta.l. w?e~ reduced is run into a mixer, where 1t IS kept flu1d t1ll 1t 1s passed into the con verter. The ingots cast from the con-verter a re not allowed to cool, but when sufficient ly solid are placed into heating furnacei, where they are kept hob till passed through the "blooming" mill, in which they are reduced in 11 passes from in~ots 16 in. by 18 in. in section to "blooms" of 8 in. square ID section. These "blooms" are again not allowed to cool but are kept hob in furnaces, or in some oases pass direct to the rail m ill, where they are reduced to 70 lb. rails in nine passes by rolls running a.t the rate of 900 ft . p er minute. The temperature at which the rolling is concluded is nowadays at or above an "orange heat " (2000 deg. to 2200 deg. Ft1hr. ); whereas in 1880 the rails were finished at a 11 cherry red," or 1400 deg. to 1600 deg. Fabr.

At the Board of Trade inquiry re the Dublin Corpora-tion, application for sanction for loans intended for the extension of theelectriclightingsystem in theoity, Mr. H. Parshall appeared as a. strong advocate ol continuous-cur-ren ts for motor work. This is a. point on which there is great difference of opinion. Eminent Swiss engineers assert that even as regards starting torque, three-phase motors are superior to the continuous-current type, and it is impossible to altogether d isregard their opinions as based on insufficient e..xperience. The ~reat sim-plicity of the alternate- current motor, wh10h should make its cost of maintenance much less than in the case of its rival, is bound to have a considerable effect in leading to their more general adoption, especially in view of the fact that even where con tinuous currents a re used in the motor, it is now frequently the case that the genera.tor.a at the main station supply altern::Lting currents only, and that to secure the direct current in the con-sumers' mains expensive rotary transformers have to be employed. Other evidence given at Dublin goes to show that there is a difficulty in securing good foundations at the site proposed for the station at Pigeon H ouse Fort. Under these circumstances it would seem that the turbo-generatora, the inven tion of a distinguished Irishman, might perhaps be adopted.

The report by Sir WiJliam Crookes, F .R.S, and Pro-fessor Dewa.r, F.R.S., on the composition and quality of daily samples of the water supplied to L ondon for tbe month ended February 28, states that of the 192 samples examined by them during the mont.h, all were found to be clear, bright, and well filtered. The rainfall at Oxford during the month was exceptionallv heavy, no less than 4.23 in. having been measured. The average fall for February was 1. 76 in., so that there is an excess of 2.47 in. The total excess for the firs t two months of this year is now 2.61 in., or 66.5 per cen t. on the 30 years' average. The report continues: " The exceptionally high rainfaJl of 4.23 in. during the month, following a long drought at this time of the year, has resulted in the organic carbon being higher, and the bacteriological purity of some of the filtered wa ters being lower, than the average of the last few months. This has been especially the case in three of the Thamt>s-deri ved waters, the filter wells of which on some occasions have given abnormally high nu m hers. So far as we can ascertain, the working of the filters has been conducted with a ll the customary care and precautions. Similar abnormal re-sults have usually followed the breaking up of a long drought. On careful examination, it is satisfactory to know that the organisms in the