¢)S,1~

~wing llone. The thanks of the Society in London fi)r the 1,'ncouragement o f

Arts~ &c. were voted to Mr. J. Fayrer, of Pentonville, for~his swing hone for sharpening razors and other articles of cutlery. One of the hones has been placed in the Society's Repository.

The exquisite edge given by the cutler to razors, lancets, and o ther line cutting instruments, can rarely be produced by those persons who are in the habit of using them. This arises partly from ignorance of the properties in which consists tile difference between a good a n d a bad hone, and partly from want of that skill and slight of h a n d i n the use of a hone, which long and constant Iwactice only can give i n perfection. 5I,'. Fayrer's hone is a plate of brass, about an inch wide~, and of any convenient length, ground to a perfectly smooth surfac~ on both sides; part o[eaeh end is cut or filed away, leaving only tyro pins, or pivots, on which the hone turns or swings. In the frame are~ two uprights with notches to receive the pivots. Two boxes are p r o - vided, one to hohl a coarser and the other a finer powdermade of o i l - stone ground down and washed over: [br tile latter, finely pounded water-of-Air-stone may be conveniently substituted.

To use the ]lone, first put on one of its sides a few drops of oil. and a little of the rougher or coarser powder, then draw along it, i n the usual manner, the edge of tile razor or other tool to be slmrpened, As the hone swings on two pivots, the surface necessarily applies i t - self quite evenly along tile edge of the blade, in whatever d i rec t ion the pressure of the hand is made that holds the tool ; and the pa r t i - cles of the powder, as tile operation proceeds, are continually heeomt- ing smaller and smaller, and theretbre giving a finer and liner edge: to the tool or blade. To finish the setting, turn uppermost the other- surface of the hone, apply to it oil and the finer powder: and p roceed as befi~re.

Metal plates, both of steel and of tin, have already been made t o serve the purpose of hones; but the application of brass as a material. for this purpose seems to be new, as well as the contrivance of h a n g - ing it on pivots, in order to accommodate itself to the varying p r e s - sure of the hand. [Trans. of Sac.for JEncour. of drts.

TRANSL/kTIONS FROM FOREIGN JOURNALS,

New rollers for Inking Lithographic Stones. [Translated for this Journal. ~]

Tile rollers used in lithography for inking the stones, consist geu e - rally of cylinders of wood covered with calf skin, and stuffed wit lx carded wool. Besides the inequalities which the surfaces of such i'o| ! - ers present, the seam uniting the two sides of the leather makes ,x ridge which spoils the uniformity of the inking, particularly when .

By request of the Committee on Publications.

Removing ,t?cld from Paper.--Imilcttion of Mezzotint. 203

large stones are used. This has hitherto been a great obstacle in the progress of the lithographic art. This ridge had been reduced~ and practice had taught a method of concealing, in part~ the defects ne- cessarily attendant upon the use of rollers with seams; but the in- convenience and many defects still remained to be remedied. M. Tudor, incited by an appeal of the Society for tile Encouragement of National Industry~ conceived tile idea of making rollers of round plates of different substances cut with a punch~ then threaded toge- ther on a cylinder of wood, pressed |orcibly one against tile other, and polished or trimmed. I[e has tried in this way chamois lea- the,', calico, aml calf skin. This last material answered best~ anti furnished rollers which were soft, without seams, and which distri- buted tile ink uniformly. M. de Lasteyrie~ a competent judge in these matters, observes that tile ordinary (seamed) rollers are very quickly worn out, while those of M. T. will not be exposed to the operation of' the same causes of wear and teat', and will, therefore~ greatly outlast tile others.

The new rollers are rather higher priced than the common ones, but it is coniidently expected that their continued manufacture will admit of a reduction in the price. M. Tudor has received a prize of 500 francs (.$100) for the ingenuity displayed in his invention.

[ Mdmorial JEn~jclopddique, ~'e.

Method of removing .~cid from the papers used in Lithographic Printing.

Most of the paper used ill copperplate and lithographic printing has an acid reaction, due, doubtless, to the processes of whitening, or to the alum used in its manufacture. This acid soon injures the tex- ture of tile lithographic stones, and after, at tnost~ thirty, impres- sions have been taken, the stone ~reaa'e8, to use the expressmn of the workmen, and the impressions are imperlect. M. Joumar remedies this greasing of the stone, in a wwy simple way ; he passes the paper intended to receive the impression, through weak lime water, which neutralizes tile acidity; he leaves it through the night thus wet and ~natted, and on the following morning eitller dries it or takes off tile superabundant moisture, keeping that degree of softness which the printing requires. 'File author of this simple and easy method of re- ,uoving tile acid from litilographic papers, ltas received a medal of the value of ~00 ti'ancs, (S40.) [Ibid.

Lithography in imitation of Mezzotint. Various attempts have been made to imitate the style of mezzo-

tinto engraving by lithography. One of the methods tried was by tampiny;. This process had given some beautiful results, but tile n,ellowness of the tints could notbe obtained. Be~itles, in sketching