SCIENCE-ADVERTISEMENTS

STANDARD

ACOUSTICSBy Alexander Wood, D.Se., Cambridge;

University Lecturer in ExperimentalPhysics.

1941. 575 pages. 310 illustrations. Manytables and diagrams. $7.00

HEAT ANDTHERMODYNAMICSBy J. K. Roberts, Ph.D. (Cantab.), Univ.

of Cambridge.1940. 3rd complete revised edition. 488

pages. 158 illustrations. 20 x 20 chart.$6.50

PHYSICAL CHEMISTRYOF HIGH POLYMERICSYSTEMSBy H. Mark, Professor of Organic Chem-

istry, Polytechnic Institute of Brooklyn.Translated from the German by K. Sinclairand J. E. Woods.

HIGH POLYMERS SERIES, Volume II1940. 353 pages. 99 illustrations. $6.50

NATURAL AND SYNTHETICHIGH POLYMERSA text book and reference book for chemists and

biologists.By Kurt H. Meyer, Professor of Organic

Chemistry, Univ. of Geneva, Switzerland.Translated by L. E. R. Picken.HIGH POLYMERS SERIES, Volume IV1942. 708 pages. 180 illustrations. $11.00

INTERSCIENCEPUBLISHERS, INC.

215 FOURTH AVENUE

T EXTSe

ORGANIC CHEMISTRYBy Paul Karrer, Professor of Chemistry,

Univ. of Zurich.Translated from the 6th German edition byA. J. Mee, Glasgow Academy.

1938. 900 pages. Illustrated. $11.00

EPHRAIM'S INORGANICCHEMISTRYBy P. C. L. Thorne and A. M. Ward,County Technical College, Guilford, En-gland.

1940. 3rd revised and enlarged Englishedition. 924 pages. 98 illustrations.

$8.00

DIFFERENTIAL ANDINTEGRAL CALCULUSBy R. Courant, New York Univ.Translated by J. E. MeShane, Univ. of

Virginia.Volume I, 1938. New revised edition. 630

pages. 136 illustrations. $5.00Volume II, 1936. 692 pages. 111 illus-

trations. $7.00

OUTLINES OFSTRUCTURAL GEOLOGYBy E. Sherbon Hills, Lecturer in Geology

in the Univ. of Melbourne, Melbourne,Australia.

1940. 182 pages. 105 illustrations. 4plates. $2.25

NORDEMAN PUBLISHINGCOM PANY, INC.

NEW YORK, NEW YORKH IlIIIIIIIIIIIII li I ll ill l1 ill l il l l l ll1 l i l li l11 l11 l l Il ll li l li ilIl 1l1l ll l1 l l l l l Ill Ill l l 11 ll 11 l1 l

till 1111 1111 11111111 1111

SEPTEMBER lly 1942 7

SCIENCE-SUPPLEMENT VOL. 96, No. 2489

SCIENCE NEWSScience Service, Washington, D. C.

THE BUFFALO MEETING OF THE AMERI-CAN CHEMICAL SOCIETY

CHEMISTRY IS contributions to the American war effortwas the keynote of the annual fall meeting of the Amer-ican Chemical Society which opened last Monday, with4,000 of the country's leading chemists gathered to hearand discuss something over 400 papers setting forth thegist of the year 's progress.

" National Survival Through Science" was the sub-ject of the presidential address, delivered Monday eveningby Professor Harry N. Holmes, veteran of the OberlinCollege faculty. More particular treatment of specialtopics at the daily sessions included papers on such war-

important subjects as synthetic rubber, gasoline and oil,alloy steels, dehydrated foods, synthetic plastics, potashand the newer chemical drugs.

There were many men well known in industry and pub-lic affairs as well as in the field of chemistry among theparticipants in the program. The list included LieutenantGeneral William S. Knudsen; Dr. Charles M. A. Stine,vice-president of E. I du Pont de Nemours and Company;Dr. Willard H. Dow, president of the Dow Chemical Com-pany; Dr. Edward R. Weidlein, director of the MellonInstitute in Pittsburgh, and many others.

Chemistry's equivalents of Distinguished Service Med-als were awarded at the meeting. The Francis P. GarvanGold Medal, honoring women in chemistry, was presentedto Dr. Florence B. Seibert, of the Henry Phipps Instituteof the University of Pennsylvania, for her distinguishedwork on the chemistry of tuberculosis. For contributionsin the field of protein chemistry, Dr. John L. Oneley, ofthe Harvard Medical School, will receive the $1,000 Amer-ican Chemical Society Prize in Pure Chemistry, given an-

nually for outstanding research by a man or woman lessthan thirty-six years old.One feature that usually marks meetings of the Amer-

ican Chemical Society was this year conspicuously absent:there were no inspection trips to industrial plants wherechemical methods are in use. This year, and for theduration, such visits are impossible because of wartimerestrictions that bar even scientists from factories whereproduction is being pushed to the utmost and even thevisits of colleagues would be a time-losing distraction. In-stead, parties of the chemists and their wives made tripsto nearby Niagara Falls.

VANADIUM, strengthener of steel for war, is now beingextracted by a new process from Idaho phosphate rockused in fertilizer manufacture. It is estimated that halfa million tons of vanadium can be recovered from the5,700,000,000 tons of phosphate rock in sight in thisdeposit. The extraction process was described before themeeting of the society by Dr. J. Perry Morgan, chemicalengineer of the Standard Oil Company of New Jersey,who developed it under the direction of Professor ArthurW. Hixson, of Columbia-University.The phosphate rock is first treated with sulfuric acid,

the solution concentrated by evaporation, and then treatedwith nitric acid. The vanadium is precipitated as vanadylphosphate, and the phosphoric acid is filtered off to beused in the making of fertilizer. The vanadyl phosphateis subjected first to live steam, then treated with ammoniagas and ammonium nitrate, which converts it into am-

monium vanadate. The ammonium is driven off as am-

monia gas by heat, leaving a residue of vanadium pent-oxide, which is the form in which vanadium is suppliedto the steel industry.Vanadium is a prime toughener of steel. It is a requi-

site in the manufacture of armor plate, crankshafts, axlesand piston rods, and other steels needed where heavypunishment will be encountered. About four pounds are

added to each ton of steel, as a rule.American steel makers have depended mainly on one mine

in Peru for their vanadium supply, with certain additionalamounts from Africa. However, war demands for< steelhave so greatly increased the quantity of vanadium neededthat new sources had to be sought. There are otherdeposits of vanadium-containing minerals in the UnitedStates, but unfortunately they are badly scattered. How-ever, the total supply of the vital alloy metal in this coun-

try will probably amount to several million tons, ifemergency requires complete exploitation.

DEHYDRATING vegetables is not simply a matter ofpeeling and slicing them and tossing them into the drier.There are a lot of tricks to the trade, and ignorance or

neglect of them will produce the inferior products thatgave dehydration such a black eye during World War Iand delayed its progress by a decade or more. Dr. W. V.Cruess, of the University of California, told of some ofthe things that must be done if dehydrated vegetables are

to be really good.First of all, the vegetables must be garden-fresh. Keep-

ing them for any length of time results in a loss of vitaminC, he said. Then they must be blanched, that is, thor-oughly scalded in hot steam, to stop the action of theirown enzymes which will spoil both quality and color ifthey are allowed to continue their activities within thecells. The practical dehydrator has to know certain neces-

sary facts about plant physiology, and apply them. De-hydration temperatures can be high at the beginning,while the vegetables still have full moisture content, be-cause the water absorbs the heat. But near the end, thetemperatures must be kept to a safe, low level.Even after the job is finished, there are still troubles

to contend with, Dr. Cruess told his listeners. Insects lovedehydrated foods, and will chew through anything butmetal or glass to get at them. They are highly absorbenttoward atmospheric moisture, and likely to spoil in con-

tact with oxygen; which again calls for special protectivemeasures.

WHILE food dehydration is attracting great attentionbecause the products can be so compactly shipped for

8

SEPTEMBER 11, 1942 SCIENCE-ADVERTISEMENTS

Why You Should UseAminco Cells . . .

* Aminco introduced the first commercially avail-able high-precision fused absorption cell in thiscountry. Aminco cells are America's recognizedstandard today. Their manufacture is super-vised by trained engineers and physicists whoAdhere rigidly to Aminco's exceptionally highstandards.

* Aminco cells are Individually hand made byhighly skilled technicians in accordance with acarefully controlled process. Each cell is pains-takingly inspected and tested. Methods consid-ered extraordinary elsewhere are routine in the Amincoplant. Dimensional tolerances of Aminco cellsare definite and guaranteed-they are in pub-lished form and you know in advance Just whatyou will get.

* The windows are fused to the bodies and can notbecome detached, thus you are assured againstloss of valuable material and time, and you ob-tain greater accuracy in your final determina-tions.

*Aminco cells are Intended for use especially infine, high-precision instruments in which the useof mediocre cells would defeat the accuracy orother virtues of the Instruments themselves.

* Aminco cells are being used by leading institu-tions whose judgment is a valuable criterion forany prospective user who wants the best.

12 Styles 387 StandardSizes Fully Describedin BULLETIN 1170-A

*

Strain-free Cell8 (Pyrex orQuartz); Baly Adjustable,Dichromate, and IrradiationCells- Raman Tubes- Hol-low Prisms. Specia' Cells

to Order.

Windows Fused in PlaceWindows and bodies are fused

Into one continuous mass (with-out joints, cement, or flux). Win-dows can not become detached.

Parallelism of Facesof Each Window:

±10 minutes.

Windows Flat Over Entire Areato Within 6 Wavelengths

Parallelism of Liquid-GlassInterfaces:

0.025 to ± 0.01 mm.

Inside Length (Between Faces ofWindows) Held to Unusually

Close TolerancesFrom + 1% to ± 0.005 mm. of

nominal length. Actual meanlength marked on each cell tonearest 0.001 mm.

Available in Pyrex, Corex "D"or Fused Quartz

Noimioth

W

AMERICA'S LEADING MICROSCOPE REPAIR HOUSE

_ DISSECTING INSTRUMENTS

MICROSCOPE SLIDES

COVER GLASSESMAGNIFIERSLENS PAPER

SLIDE BOXES

We repair any make of microscope.Cash for your surplus or obsoletemicrotomes, microscopes, objectives,oculars, etc.

Microscopes of all models urgentlyneeded, even bare stands-any make._ 21 sI)[' 'rl s ~~~~~~~PROMPT

AMERICAN MADE DISSECTING SETS ECFNIMICAL3B (illustrated) with all metal scalpel $1.15 each. Order now formediate or future delivery at current prices. Write for quotations oner popular sets. Special sets made up according to your specifications. THE GRAF-APSCOCOMPANY

PROMPT DELIVERIES. 5868 BROADWAY

'E BUY AND SELL USED MICROSCOPES CHICAGO, ILL.

Write for our new catalogue if you do not have a copy

9

-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

10

overseas use, quick-freezing of fish, meat, fruits andvegetables for home consumption is not being neglected.Frozen fish is in such great demand, according to DomenicDeFelice, of the New York State Agricultural ExperimentStation, that hitherto unused species have had to beadded to haddock, flounder and other first favorites forfilleting. The frozen berry industry in the Pacific North-west has about reached its limit, but is expanding else-where in the country. Boned and packaged meats are

being frozen in large quantities for Army use.

THE canning industry took a body blow when Jap ag-

gression cut off hitherto abundant tin supplies, but can-

ners are putting up a good fight to do their share towardnational food conservation, was stated by E. J. Cameronof the National Canners Association. Electrolytic tin-plate, which requires far less tin than the old method, andpretreated steel plate, which requires no, tin at all, are

coming into increasing use. Low-tin and tinless soldersalso are winning their way.

DRINKS as well as foods came in for attention. Dr.A. J. Liebmann and M. Rosenblatt, of the Selenley Dis-tillers Corporation, told of researches on the chemistry ofaging whiskey which they have been carrying on for fiveyears, with an array of about 560 barrels of liquor as ex-

perimental material. All whiskey is colorless when it isfirst run into the barrel, they stated. It gains color, aromaand most of the other qualities prized by the proverbial"judge of good liquor" through long contact with thewood. Three things happen: (1) Extraction of sub-stances from the wood; (2) oxidation of some of the orig-inal substances in the liquor and also the material ek-

tracted from the wood, and (3) reaction between theoriginal substances and those from the wood.

THE postwar automobile will burn gasoline of 150octane rating, and it will never be necessary for the fill-ing station attendant to put more water in the radiatorbecause the cooling system will be permanently sealed.When you get home from your ride, you'll put the car ina garage with plastic-and-plywood walls and a stainlesssteel roof.Your house will be built of the same materials, strong

yet so light that two men will be able to lift the wholewall of a room as they put it up.

These are items from a vision of the future presentedin an address by Dr. Charles M. A. Stine, vice-presidentof E. I. du Pont de Nemours and Company. They aren'tjust dreams, he explained; the things actually exist now,at least on an experimental basis, but are at presentabsorbed into the war effort.

Other new accomplishments in scientific technologyqwerelisted by Dr. Stine: glass that is unbreakable, glass thatwill float, wood that won't burn, shoes that contain no

leather, window screens without wire, machinery bearingsnot made of metal. Post-victory production of consumer 's

goods will reach heights undreamed of in prewar days,the speaker predicted. We have built an immense in-

dustry that turns out more light metal in a year than was

formerly produced in a decade, with corresponding vol-

VOL. 96, No. 2489

umes in such things as special steels, plastics, syntheticfabrics, fuels.Having seen how abundantly we can produce for war,

the American people will insist on abundance in time ofpeace, Dr. Stine forecast. Slums must be cleared away,

he declared; the space they leave should not be filledwith other buildings, but put to use as close-in airfields.Better nutrition for everyone, based on recent researchesin food chemistry, is imperative for the maintenance ofa population of high industrial productivity.No doubt, some will become alarmed over the possible

displacement of old materials and old industries. Changesof a drastic nature are inevitable, but they seldom resultin the hardships that the timid predict. . . . Let our

swords be mighty, and mighty indeed will be our plow-shares.

MEATLESS days, even whole meatless months in an emer-

gency, need have no nutritional terrors, if a supply ofsoybean, cottonseed or peanut flour is available, the Amer-ican Chemical Society heard in a report by Theodore F.Zucker and Dr. Lois Zucker, of Columbia University.These flours, which are made from the seeds after theoil has been extracted, are very rich in protein and cer-

tain vitamins, so that they should prove highly valuableas additions to ordinary wheat flour, making bread a more

nearly balanced diet. It is possible to make a meatlesssandwich just by buttering two pieces of this mixed-flourbread and slapping them together. The "meat" is in-visibly present, incorporated in the bread itself. Bothsoybean and cottonseed flours have distinctive tastes towhich the eater needs to become accustomed. Cottonseedflour makes a yellower loaf than most of us are used to.On the other hand, it is very cheap-five cents a poundon the current market. Peanut flour offers less difficultyso far as taste is concerned, but its price is considerablyhigher.

Test batches of bread were made up out of variousmixes of these seed flours with wheat flour and triedout on rats, which throve very well on them, needing no

other source of proteins. They also got sufficient quanti-ties of two necessary vitamins, thiamin and riboflavin,from the seed flours.

ANOTHER by-product of agricultural industry that may

find profitable use through chemical handling is bagasse,the woody waste left after the sugary sap has been crushedout of sugarcane. Professor Donald F. Othmer andGeorge A. Fenstrom, of the Polytechnic Institute ofBrooklyn, described their experiments with this material.From a ton of dry bagasse, heated in a dry still, theyobtained 35 pounds of acetic acid, one and a third gal-lons of crude methanol (wood alcohol) and 750 pounds ofcharcoal. The acetic acid and methanol are in large de-mand as industrial solvents, and charcoal is a familiardomestic fuel in the warm lands where sugarcane is grown.The experimenters pressed it into briquets for marketing.

WORLD WAR I caught us short on potash, necessary alikefor farm fertilizer and chemical manufactures. It isn 'thappening this time. That the pre-1914 German monopoly

SCIENCE-SUPPLEMENT

SCIENCE-Si

of this important mineral has been broken by the develop-ment of an American potash industry, was pointed out byDr. George R. Mansfield of the U. S. Geological Survey.At present, only the highest grade potash deposits in theWest are being worked, but these alone would be enoughto supply American needs for 200 years, at present ratesof use. In addition there are large quantities of otherpotash minerals that are not profitable to exploit atpresent, but may be made so by future technical advances.How potash is helping the United States to win the war

was outlined at the same symposium by Dr. J. W. Turren-tine, of the American Potash Institute. With plenty ofthis highly important fertilizer element now available,farmers need not stint their fields as they had to duringthe first World War, but can use all they need. Thismeans bigger crops from the same acreage, which in turnmeans more bread, more meat, more vegetable oils forourselves and our allies.

IF Nazis or Nips resort to polecat warfare and spray

poison gases on the commissary stores, that doesn't neces-

sarily mean that the troops will have to go hungry. Ofcourse, mustard gas instead of mustard on your meatwould make it unfit to eat-but if it is wrapped or pack-aged as well as most commodities are now-a-days it willstill be good to eat after the covering has been decon-taminated and removed. Do 's and don It 's or anti-gas pro-

tection for foods were reviewed by Dr. Sidney H. Katz,of the U. S. Chemical Warfare Service's main arsenal atEdgewood, Md. The most dangerous of so-called poisongases, from the food-contamination viewpoint, are notreally gases at all but finely atomized liquid sprays. Thesecling to anything they touch, and unless recontaminatedwill remain dangerous for days. *Decontamination is nota job for just any one; it must be carried on under thedirection of an offieer trained for this particular job. Thebest protection against chemical contamination, thespeaker stated, is afforded by the most conventional offood packaging-tin cans and glass jars. Cellophane isvery good for excluding the insidious poisons, especiallywhen the package seams are well sealed. Tin foil andaluminum foil wrappings also are effective, but only iftightly applied. Simple paper or cloth bags are bad, butseveral layers of either paper or cloth give fair protection.Corrugated cardboard is good, especially if it has beengiven a glazed coating. Natural rubber is not as effectiveagainst war chemicals as some of the synthetic rubbers.

CHEAPER riboflavin (vitamin B,) for bread enrichmentis the prospect held forth by Dr. Jonas Kamlet, of MilesLaboratories, Inc., New York City. Ribose, a specialsugar which is the only raw material from which riboflavincan be elaborated, is produced by a strain of yeast thatis fed on waste sulfite liquor from paper-pulp mills, one

of the most troublesome of all industrial wastes. Theprocess was developed first at the National Bureau ofStandards, Dr. Kamlet stated, and the first commercialinstallations are two plants set up in Canada by a Swedishengineer, G. Heijkenskjold. Similar plants will be builtin the United States after the war.

7PPLEMENT 11

DYES made directly from soft coal, instead of the time-honored coal tar, were described before the meeting byDr. H. B. Charmbury, of the Pennsylvania State College.The coal is first treated with nitric acid, to obtain a

foundation material which is then treated with organicacids and inorganic alkalis to produce the dyes themselves.These direct-from-coal dyes were tried by Dr. Charmburyon animal fibers like silk and wool, vegetable fibers likecotton and linen, and synthetics like rayon and nylon, withsuccessful results.

PHYSICS supplemented chemistry in a search for causes

of the stretchy, bouncy behavior of rubber when a group

of physicists from Notre Dame University presented threepapers before their chemical colleagues. The chemistsremembered the classic contributions of a former colleaguefrom the same university, the late Father Nieuwland,pioneer in the creation of synthetic rubber, as theylistened to the presentations of Dr. Eugene Guth, Dr. S.L. Dart, Dr. R. L. Anthony and Dr. L. E. Peterson, to-gether with Dr. H. M. James, of Purdue University. Thepicture they gave was one of a curious substance that hassome of the behavior features of a solid, some of a liquid,and some even of a gas. Explanation is to be found, thespeakers suggested, in the shape of the individual rubbermolecules, which are long, spiral, wormlike affairs thathook their coils together like tangled springs. One ofthe gas-like properties of rubber is its curious sudden risein temperature when it is stretched, and its cooling whenit contracts. This can be tested by any one, merely bytouching the lips to a quickly stretched rubber band. TheNotre Dame scientists have made a quantitative studyof this strange temperature effect in rubber, with sensitivescientific instruments. Their data are expected to be ofvalue in the future development of both natural andsynthetic rubbers.

COAL is commonly thought of primarily as food forthe mouths of factory furnaces, rather than as a materialof great benefit to farmers-beyond keeping their houseswarm, perhaps. But that farmers are beneficiaries of themining and coal-processing industries in a number of ways,

was pointed out by Dr. Hubert G. Guy, of the KoppersCompany, Pittsburgh. Ammonia compounds, by-productsof the coke industry, have become one of the principalsources of fertilizer nitrogen. Naphthalene, a by-prod-uct of coal carbonization, is widely used to combat severalkinds of insect pests, as well as in preserving stored hides.Synthetic plant hormones, also originating from coal,hasten the formation of roots on cuttings and are sprayedon orchard trees to prevent premature dropping fruit.Other coal products are used as food colorings, wood pre-

servatives, disinfectants and parasite killers.

ANTHRACITE coal is coming into wide-spread use forfiltering city water supplies, replacing the long-used sandbeds, according to Dr. Homer G. Turner, of the AnthraciteEquipment Corporation, New York. During the pastseven years anthracite for filter use has been shipped toevery state in the Union and to Alaska, Canada, SouthAmerica, England, Australia and Iran.

SEPTEMBER 11, 1942

SCIENCE-ADVERTISEM.ENTS

Vision for VictoryT HE future of the world today depends on

American industry's capacity to produce theimplements of war. The Soldiers of Industrial Pro-duction must be welded into history's most efficientfighting organization before the spectre of aggres-sion can be dispelled.

Because most skills depend on efficient function-ing of the eyes, and because nearly one-third of thepeople of the nation still have uncorrected faultyvision, a valuable public service is performed bycalling attention of American workmen to theimportance of proper care of their eyes.

Taking as its theme "Vision for Victory," an

advertising campaign (one insertion of which is

reproduced above) is now appearing in an extensiveschedule of nationally-circulated magazines. Theprogram is sponsored by the Better Vision Insti-tute, a non-profit service association, supported bythe manufacturing, distributing and professionalbranches of ophthalmic science.We also hasten Victory who make minds keener

and hands surer through the improvement ofhuman vision.

BAUSCH & LOMBOPTICAL COMPANY * ESTABLISHED 1853

AN AMERICAN SCIENTIFIC INSTITUTION PRODUCING OPTICAL GLASS AND INSTRUMENTSFOR MILITARY USE, EDUCATION, RESEARCH, INDUSTRY AND EYESIGHT CORRECTION

VOL. 96; No. 248912

SEPTEMBER 11, 1942SCIENCE-ADVERTISEMENTS 13

A Valuable Volume for Reference...

LIST NO. 33-EASTMAN ORGANIC CHEMICALS1942 catalog of the world's most completestock of organic chemicals

More than 3400 compounds-68 new items-alphabetically listed with specifications.

Nine convenient groupings of related compounds:1. Special Reagents2. Special "-Spot Test" Reagents3. Vitamins and Related Products4. Hydrogen Ion Indicators5. Amino Acids-6. Carcinogenic Hydrocarbons7. Liquids for Refractive Index Determinations8. Alkaloids9. Sugars._ _

Write for a free copy of this caialog today_

EASTMAN KODAK COMPANYKODAK Chemical Sales Division Rochester, N. Y.

STOPWATCH REPAIR SPECIALISTSRARE CHEMICALS X a,(All makes)Due to the shortage of stop-

rTH watches, may we suggest you send* * > > 1HE EDWAL LABORATORIES them to us for estimates. Allis an organization of consulting chemists and engineers. makes repaired. Our specialistsIn its founding years it engaged primarily in industrial will rebuild them like new. Oneresearch, analysis and control work. Succeeding years year guarantee. Send by parcelrevealed the necessity for entering into the small scale post or express to:

manufacture of new chemicals which were needed for MEYLAN REPAIR DEPT.research problems and which could not be obtained 264 West 40th St., New York City, N. Y.elsewhere. This led in turn, to the production forsale of a number of pure chemicals which at the timewere not commercially available.

Although today facilities for large scale manufacture La iotte pH Test Papersare available, an important part of our work is stilldevoted to the small lot production of new and rare As an aid in the approximate estimation of the pH

chemicals. This service is in the hands of competent of various solutions and substances, we have pre-

chemists, and is offered to all firms, individuals or pared a series of sensitive test papers from ourschools engaged in research, development or production. standardized pH indicators. They are supplied inA special "Small Lot Price List, No. 11" will be sent vials containing 100 strips of the paper and are

with our catalog when requested. available within a range of 3.8 pH to 9.6 pH. Price50 cents per vial for each indicator range-f.o.b.

TUC rnzukl I *DnD&TnDI~~~Batinre Md.THE EDWAL LABORATORIES, Inc. B;ie Chica1 ProductsCo.732 Federal Street CHICAGO, ILLINOIS Dan t te, TCwsnc raltimore. Md.

AJUJ11 to. JF.L dh-W-P --

SCIENCE-ADVERTISEMENTS 13SEPTEMBER 11, 1942

14 SCIENCE-ADVERTISEMENTS VOL 96, No. 248~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Scene is one ofie Curtius-JP'ightAirPlan Division srom fortraining U. S. Army ground mr

IIisual Training dons olive drabHow to take a fighting plane apart

and put it toshr Wain-how$ to"keep 'em flyiag'-...r coat

enemy tactics-h~ war

quickly-is theSpeed in impartng a cdisr udW-

standing to millics of ar g_-millions of civilisadmis attained best by vr w'_Dramatically, tlwy al1ject charts, draw*p,-detailed close-ups. To ,tain the graphic big~

words of the instructor. Seeing becomesknowing how. Knowing how is theaMwer!*t ~~* * *

Optical instruments are so vital to war, pro-iction for war and public health that the ta-t40s needs absorb practically all of Spencer'sgrtly increased production.

s . . * * *

encer LENS COMPANYBUFFALO, NEW YORK

SCIENTIFIC INSTRUMENT DIVISION OFAMERICAN OPTICAL COMPANY

14 SCIENCE-ADVERTISEMENTS VOw. 962 No. 2489