THE INDUSTRY OF ALL NATIONS.

is often used. The fibre, the whiteness, the fineness, the sizing, the calendering,the thickness, the compactness, its size, weight, age or set, strength and price,are all very variable elements, and are all important in estimating quality andadaptedness. Before printing, the sheets, in most cases, require to be wellmoistened.

Autographic printing is very extensively employed in Europe for printinglimited numbers of circulars and other commercial papers, forms for administra-tive and judicial purposes, scientific programmes and courses of instruction, andindeed for any matter of which only a limited number of copies is required. Itis also considerably used for facsimile writing, but as the autographic papermust be specially prepared and carefully protected from stains, as the ink toomust be oily and not easy to use, connoisseurs will not find autography veryinviting. In this country, at least, fac-simile copies are usually traced and trans-ferred in pencil to the stone and then inked. In fact, autography is not hereused to any considerable extent, as the job printers chiefly do the work done bythe process in Europe, or else the writing is written in reverse on stone by a pro-fessed lithographer. Bonds, stock checks, ornamented cards, &c., are thus pre-pared to a great extent.

Engraving on stone is much employed for maps, plans, mechanical, architec-tural, botanical, and other outline drawings. The lines, scratched into the stonewith a point, lack the clearness of copper lines, or even of pen lines on stone,yet with care, decidedly fine drawings can be thus executed. As these engravingsgive proofs adapted to transferring, there is almost no limit to the numbers whichcan be obtained from a well engraved stone. The engraved lines take the inkless readily than drawings or transfers, hence the printing of engraved stones isusually quite to the prejudice of the ink lines produced, done from transfers, ifconsiderable numbers are desired. The ruling machine, and, if in skilful hands,the etching process, may be made to co-operate with the graver to good effect.Engraving on stone for maps, for botanical illustrations, &c., is much used inGermany and France, as its cost is only about 30 per cent, of that tor copperengraving, and as from 10,000 to 12,000 may be printed from one stone withoutdeterioration. The “ Flora of Brazil,” contains 1,700 plates thus engraved byKnecht. The chief difficulty is in procuring the printing from engraved stones.Engraving in relief is a delicate and critical etching process not much in use. Itis, in fact, but a modification of Senefelder’s first discovery, and does not admitof sufficient relief to print in the manner of wood-cuts.

Crayon designing consists simply in drawing on stone with a fat crayon. Butthis simple process requires more precaution, more acquired skill, more delicacyof touch than one can readily conceive, and the artist must carefully watch thegrain of the stone, its thorough protection, the working of his crayon, and a mul-titude of minor things indicated by experience. He must guard against the needof erasures, and as far as possible avoid retouching. Withal, he must he anartist, realizing the exact effect of what he is doing. The style in two crayons ,now quite common, was used by Manlich in 1805, and revived subsequently byHarding in his Swiss and Italian views. For this the stone is prepared so as toprint a uniform tinted ground, on which the dark crayon drawing is overlaid andthe white crayon lines and lights are made by erasing the ground tint, and scrap-

ing away the grain more or less completely, sometimes even hollowing out thebrightest lights.

Several processes of grading shades or of aqua-tinting have been used, otwhich Senefelder’s, Jobard’s, Hancke’s, Knecht’s and Lcmercier’s are the mostconspicuous. None are quite what is desirable, nor is it likely that any processcan reach the main difficulty, which is that printing soon impairs or varies themost delicate shades. Lemercier’s seems the simplest possible. When thecrayon or ink drawing is ready, scatter crayon-dust over it and brush it witha soft brush, so as to give the shade required; then retouch with the crayon inkor stamping crayon, until the desired tone is reached. He has used this processin chromolithography, so as to save some of the color-printing stones. Theprinciples of pen and brush drawing on stone are so like those of crayon, that itwill suffice to mention them and their great utility and convenience for manyvarieties of work. They require special practice, study and manipulation.

Chromolithography is the name given by Englemann to his process (an ex-pansion of Senefelder’s idea) for printing from several successive stones, a seriesof colored inks, which, by their combination and superposition, realize the finaldesign in the colors desired. The great difficulty, aside from the procuring ofgood color inks, is in securing an accurate register or superposition in the suc-cessive printings, so as to preserve the correct relations of the various coloredlines and masses, a difficulty increasing rapidly with the size of the print. Thedrawings of the parts for each color-stone are made by tracings, and the effectof their relative intensities, superpositions, and contrasts must be realized bystudy, practice, and special comparisons. The difficulties of this process are onlygreat when the lines of tint are complicated and delicate, but ordinary tintprinting and gilding are not peculiarly trying.

Copper or steel plate transfers are made by first taking a plate impression intransfer ink, on a paper prepared by a coating with a soluble layer usually com-posed of starch, gum arabic and alum. This impression is laid face downwardson a clean stone, run through a lithographic press and wetted on the back. Thepaper is then stripped off, leaving the ink adhering to the stone. The starchlayer is duly washed away, when the transferred ink of the plate impressionalone remains on the face of the stone, which is washed in acidulated and gumwater as usual, and is then in condition for printing. Transfers from engravedstone to stone, from autographic writing to stone, or from letter-press to stone,are all conducted on similar principles. Transfers from steel and copper platesare very extensively used for printing maps, atlases and checks.

These are the chief lithographic processes, on which much more might besaid, except for the prohibition of space. They all exist among us. They areall represented at the Crystal Palace. We must not venture on specifications ofmerit or demerit in the specimens there exhibited, but the foregoing generalsummary of lithographic history and processes may provide others with some-what better means of appreciation and criticism. We thus leave the subject,hoping that we may live to see lithography so far advanced in America, thatour products in this beautiful art can safely count comparison with the bestspecimens from Paris and Munich.

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LIGHT CARRIAGE; BY B. M l KlN'8TRY. NEW-YORK,