of the second lever is in the most favourable position to be operated upon powerfully by the connecting-rod proceeding from the handle N. When the impression is produced, two balance weights act in concert to return the handle N, and raise up the platen.

The testimonies in favor of this press, by almost every master-printer who has used it, prove it to be the most complete press now in use; and at present appears scarcely susceptible of much improvement.

Several other presses are now in use, particularly the Albion press; but as they are somewhat similar in construction to the Columbian, though not so well approved, a particular specification need not be given. The Ruthven or horizontal press, invented by Mr. John Ruthven of Edinburgh, differs materially from all others, in the platen being moveable, and the types stationary. But, as it requires that a workman should almost learn his business over again to work at it, it is now seldom used. A beautiful and well-made press has lately been introduced into use by Messrs. Newman and Gillson, of Newark. Its power is produced by the use of inclined planes, and, these being fixed in a box which is well supplied with oil, the usual inconveniences experienced in that mode of obtaining pressure are in a great measure obviated. For all light work this press perhaps equals any press in use; but it is not adapted for large and heavy forms.

Several attempts have been made to apply a self-inking apparatus to the common press, and numerous patents have been obtained to this purpose; but as nothing has to this day been produced at all likely to succeed, however laudable and ingenious the attempts, we shall not supply any description of them.

Of machine printing.-Previous to the introduction of machines into the business of printing, the press department was one of great labor and difficulty, and the number of copies of a newspaper, which could be printed within the hour, seldom exceeded 750, even with extraordinary exertion. The consequence was, that in newspaper offices, where the circulation was extensive, it was found necessary, in order to get the paper published in time, to compose two or more copies, so that by going to press at the same time, the demands of the public might be complied with; thus occasioning an enormous increase of expenditure both in the compositors' and press departments. In a newspaper circulating 7000 or 8000 copies, this expense, annually could not have been less than £2000; all of which has been saved by the introduction of machines, which are worked by steam or hand.

The cylindrical mode of printing, which, in contradistinction to the old process, is called machine printing, was invented by the late Mr. Nicholson, well known in the scientific and literary world, who took out a patent in the year 1790, though it does not appear that his plans and experiments ended in any actually practical result. Whether M. König, who at a later period more successfully attempted to print by machinery, was indebted to Mr. Nicholson for his elementary principles, or whether almost the same ideas

spontaneously occurred to each individual, is a question that can only be satisfactorily solved by the former. Thus much is certain, that Mr. König's labors were the first which produced any fruit; and, surely, more is due to him who, after years of persevering toil, succeeds in the application of hitherto unapplied principles, than to one of whom we can only say that he was simply the first to suggest ideas, since no evidence is offered of their ever having been acted upon.

M. König, by birth a Saxon, and by occupation a printer, many years ago conceived it possible to print by steam, though he then expected no more than to be able to give accelerated speed to the common press; to which end his first efforts were bent. As from the nature of such an undertaking, considering the state of scientific pursuits in his native land, he could calculate on little success unaided by others, and failing in his application for encouragement and support at the hands of the most eminent printers in several of the continental capitals, he turned his eyes towards England. Arriving in London, about 1804, he submitted his scheme to several printers of repute, who, not being disposed to incur the risk of property which a series of experiments were sure to entail, and perhaps, placing little confidence in a successful issue, received his overtures very coolly; and it is probable his applications in this country would have shared the fate of similar attempts abroad, had he not finally been introduced to Mr. Bensley, senior, who, attracted by M. K.'s plans, speedily entered into an arrangement with him. After a short course of experiments on the fabrication of a press which should have accelerated motion, and at the same time render the work of the man who inks the type unnecessary, the above gentlemen were joined by Mr. G. Woodfall and Mr. R. Taylor, the former of whom, however, soon retired; the remaining three, in no wise discouraged by the tediousness and expense which all who are conversant with the progress of any invention in machinery well know to be unavoidable, persevered amidst unforeseen perplexities, which were doubtless not diminished by the party's deficiency in practical mechanical knowledge. It was at length discovered that the intended improvement of the common press could not be brought to bear, and that much labor and prodigious expense would be thrown away, unless some radical alterations were invented. CYLIN DRICAL printing was now thought of, and, after some two or three years of renewed exertion, a small machine was brought forth, the characteristic of which was, that instead of the printing being produced by a flat impression (similar to the press), the sheet passed between a large roller and the types still flat; and, in lieu of the oldfashioned balls, used by hand to beat over the types, and to communicate the ink to their surface, skins were strained round smaller rollers on which it was contrived to spread the ink, and under which the form, i. e. the frame in which the types are fixed, passed in its way to the printing cylinder. Considerable promise of success attended this production; and, after continued experiments, it was deemed practicable to

extend the general principles to a more powerful machine. To print a newspaper was considered highly desirable; and on exhibiting to Mr. Walters, proprietor of the Times newspaper, the machine already erected, and showing what further improvements were contemplated, an agreement was entered into with that gentleman for the erection of two large machines for printing his journal. So secret had been the operations of the patentees that the first public intimation of their invention was given to the reader of The Times on Monday, the 28th of November, 1814, who was told that he then held in his hand one of many thousand impressions thrown off by steam. At this time but few persons knew of any attempt going on for the attainment of the above object; whilst, among those connected with printing, it had been often talked of, but treated as chimerical.

The machines at the Times Office, cumbrous and complicated as subsequent improvements have made them appear, were yet in many respects admirably adapted to the purpose for which they were erected.

The next advance in improvement was the manufacture of a machine for Messrs. Bensley, distinguished from those before mentioned by the mode of perfecting (or printing on both sides), so that the sheet of white paper is placed in the feeder and delivered from the machine printed on both sides! In addition to the essential difference between this machine and those previously made, it came forth with many obviGus improvements, though still unquestionably complex:-and for the first attempt at effecting register (causing the pages to fall precisely on the back of one another), a greater degree of success than might have been expected was attained, subsequent experience showing the many difficulties to be surmounted in the accomplishment of this object. Deficiencies were now detected in the inking: the strained skins were found uneven in their surface; and attempts were made to clothe the rollers with an elastic preparation of glue, treacle, &c., which has at length attained perfection.

By this time the invention had attracted the attention of various individuals, who thought the manufacture of printing machines an easier task than they afterwards found it to be; and far the greater number of attempts, we believe, failed almost as soon as undertaken. A machine, however, similar in its capacities to that last mentioned, but much more simple in its construction, has been brought out, under the direction of some eminent English engineers. It was not long before these gentlemen were requested to apply their inking apparatus to Messrs. Bensleys' machine, and at one stroke, as it were, forty wheels were removed-so great was the simplification: and at the same time the defects of the former system, of communicating the ink to the types, were most effectually remedied. Massive and complicated as it was, yet as an immense expense had been incurred in its erection, Messrs. Bensley went on using their machine until the destruction of their establishment by fire in 1819. And, even after the rebuilding of the premises, the machinery, which had been

only partially damaged, was reinstated, and worked for some time it has now, however, given place to two large and admirable machines built on the improved plan, which, when inspected by a judicious eye, can create only wonder at the heretofore circuitous manner adopted to attain ends so apparently within easy reach. The original machine contained upwards of 100 wheels; whereas the new machine, with about ten wheels, accomplishes, in point of quantity, exactly the same object, with a marked advantage in regard to the quality of the printing. Another important point respecting the new machine is, that it occupies scarcely half the space of the original one.

This machine, notwithstanding the improvements which had been made upon it, has lately been replaced by one made by Augustus Applegarth, esq., several of whose machines are at present in use in the metropolis; and recently several have been exported to the continent. All the machines of his construction are worked by steam; but there are others which have for some years been brought into use which are turned by a fly wheel; and of course have the advantage of being far less cumbersome, and more applicable to the general purposes of the trade. One was invented by Mr. W. Nicholson, of London, for which a patent was obtained 29th April, 1790; a second by Mr. Bacon of Norwich, and made by Bryan Donkin, esq., of London; another was the invention of the late Charles Brightly, esq., of Bungay, and executed by the same engineer; none of them, however, have been brought into practical adoption, though they each possessed a considerable share of merit, and were constructed at a very great expense.

The adoption of printing machines rendered necessary a new mode of distributing the ink upon the type, and which is now transferred to the common press. The original mode was to moisten sheep-skins in liquor, to fasten them round a ball of wool, and then, having procured two of them, the ink was distributed on the surface of each by working them together. This is now entirely superseded by the use of rollers. These rollers are a composition of glue and treacle, which, when heated into a liquid state, are cast in a mould, round a cone of hard wood; and, when cold, are extracted from the mould, and are soon fit for use. This method of inking forms one of the most valuable improvements in modern printing; as it not only affords considerable ease to the workmen, but is calculated to perform the operation with much greater regularity and certainty.

The machines worked by hand now most in repute are those manufactured by Mr. D. Napier. They print both sides the sheet at one operation; and are calculated to do the work of about six or seven presses. This ingenious mechanist is now contriving one for printing newspapers, which is estimated to take off 300 impressions per minute,-a speed almost incredible. As this with some other machines for printing by the same engineer, are not yet completed, we must refer a minute description of them to the article TYPOGRAPHY, which see.

PRINTING, COPPER-PLATE, requires some notice, though we hardly know a modern art or 'trade that has been so little improved in the mode of conducting it. It is performed by a machine called the rolling-press, which may be divided into two parts, the body and carriage. The body consists of two cheeks of different dimensions, ordinarily about four feet and a half high, a foot thick, and two and a half apart, joined at top and bottom by cross pieces. The cheeks are placed perpendicularly on a wooden stand or foot, horizontally placed, and sustaining the whole press. From the foot likewise rise four other perpendicular pieces, joined by cross or horizontal ones, which may be considered as the carriage of the press, and as serving to sustain a smooth, even plank, about four feet and a half long, two feet and a half broad, and an inch and a half thick; upon which the engraven plate is to be placed. Into the cheeks go two wooden cylinders or rollers, about six inches in diameter, borne up at each end by the cheeks, whose ends, which are lessened to about two inches diameter, and called trunnions, turn in the cheeks between two pieces of wood, in form of half moons, lined with polished iron to facilitate the motion. The space in the half moons left vacant by the trunnion is filled with paper, pasteboard, &c., that they may be raised and lowered at discretion; so as only to leave the space between them necessary for the passage of the plank charged with the plate, paper, and blankets. Lastly, to one of the trunnions of the upper roller is fastened a cross, consisting of two levers or pieces of wood traversing each other. The arms of this cross serve in lieu of the handle of the common press; giving a motion to the upper roller, and that to the under one; by which means the plank is protruded, or passed between them.

The printing is performed nearly as follows: The workmen take a small quantity of the ink on a rubber made of linen rags, strongly bound about each other, and with this smear the whole face of the plate as it lies on a grate over a charcoal fire. The plate being sufficiently inked, they first wipe it over with a foul rag, then with the palm of their left hand, and then with that of the right; and, to dry the hand and forward the wiping, they rub it from time to time in whitening. In wiping the plate perfectly clean, yet without taking the ink out of the engraving, the address of the workman consists. The plate thus prepared is laid on the plank of the press; over the plate is laid the paper, first well moistened, to receive the impression, and over the paper two or three folds of flannel. Things thus disposed, the arms of the cross are pulled, and by that means the plate with its furniture passed through between the rollers, which, pinching very strongly, yet equally, press the moistened paper into the strokes of the engravings, whence it licks out the ink.

PRINTING OF CALICO. The art of printing in colors is intimately connected with many of the chemical processes we have already described under the article DYEING; we shall therefore avoid any unnecessary repetition of those details by occasional references to the various sections of that treatise. This ingenious art

consists in dyeing cloth with certain colors or figures upon a ground of a different hue. The colors are usually fixed by mordants that have various degrees of chemical affinity for the body to be employed.

The art of calico printing is of considerable antiquity, and we have seen some Egyptian cotton dyed by figured blocks many hundred years old. A similar process has long been resorted to in the Sandwich Islands, though they usually employ a large leaf as a substitute for the block. A popular view of the process of printing calicoes may, however, be furnished prior to a more scientific analysis of the various processes. Some calicoes are only printed of one color, others have two, others three or more, even to the number of eight, ten, or twelve. The smaller the number of colors, the fewer in general are the processes.

One of the most common colors on cotton prints is a kind of nankeen yellow, of various shades, down to a deep yellowish brown, or drab. It is usually in stripes or spots. To produce it, the printers slightly coat a block, cut out into the figure of the print, with acetate of iron, thickened with gum or flour; and apply it to the cotton, which, after being dried and cleansed in the usual manner, is plunged into a potash ley. The quantity of acetate of iron is always proportioned to the depth of the shade. For yellow the block is coated in a similar way with acetate of alumina. The cloth, after receiving this mordant, is dyed with quercitron bark, and then bleached. Red is communicated by the same process; only madder is substituted for the bark. The fine light blues which appear so often on printed cottons are produced by applying to the cloth a block covered with a composition, consisting partly of wax, which covers all those parts of the cloth which are to remain white. The cloth is then dyed in a cold indigo vat; and after it is dry the wax composition is removed by hot water. Lilac, flea brown, and blackish brown, are given by means of acetate of iron; the quantity of which is always proportioned to the depth of the shade. For very deep colors, a little sumach is added. The cotton is afterwards dyed in the usual manner with madder, and then bleached, Dove-color and drab, by acetate of iron and quercitron bark. When different colors are to appear in the same print, a greater number of operations are necessary. Two or more blocks are employed, upon each of which that part of the print only is cut, which is to be of some particular color. These are coated with different mordants, and applied to the cloth, which is afterwards dyed as usual.

Dr. Ure furnishes the following important observations on calico printing, for which he states that he is indebted to a much esteemed friend, who unites scientific knowledge to practical skill. It occurs in the second volume of Berthollet's Art of Dyeing.

To bleach cloth for printing, it is first of all to be singed, and then steeped in warm water (sometimes with an addition of spent ley) for a day or two. It is then well washed and boiled in potash ley, five different times. For 2000 lbs. (original weight) of cloth, 1000

6. Blue grounds, with a red and white resist together.

7. Chemical or spirit colors.

1. Single colors are called plates from their being generally printed with the copper plate. This process consists generally in printing a mordant upon the cloth; which mordant attracts a coloring matter when the cloth is dyed. The mordant is different, according to the color that is wanted.

For black. An acetate of iron is used of the specific gravity 1.040.

For purple. An acetate of iron, specific gravity 112, with six, eight, or twelve times its volume of water, according to the shade of color required, and the mass to be printed.

For red. A solution of three pounds alum in a gallon of water, one half of which is decomposed by acetate of life or lead.

For chocolate. Mixtures of acetate of iron, specific gravity 1-12, with red mordant, in the proportions of one to two, four, six, according to the shade.

Each of these mordants is thickened with flour, or in some cases with gum, and printed upon the bleached cloth. After being exposed to the air for a few days, in a warm room, the goods are taken down and passed through the dung copper at a heat of from 150° to that of boiling water. They are then washed, and winced in another clean dung copper, at a lower degree of heat than before, and then washed again. They are now ready to be dyed.

All the colors last mentioned, viz. black, purple, red, and chocolate, are dyed with madder and sumach, except purple, in which the sumach is omitted. Different quantities of madder are used, according to the quantity of color on the cloth, from one pound per piece of twenty-one square yards, to three and even three and a half pounds; the sumach about one-eighth of the madder. The goods are entered when the copper is cool, and the heat is brought up gradually during two or three hours, and sometimes the ebullition is kept up for a quarter of an hour; the pieces all the while being turned over a wince, from the one side of the copper vessel to the other. They are then washed, and boiled in bran and water ten or fifteen minutes. If they have much white, they must be branned a second and a third time, washing between each operation. To complete the whitening, they are spread upon the grass for a few days; or what is

more expeditious, and more generally practised now, they are winced a short time in a warn but weak solution of chloride of lime.

For indigo blue. A strong solution of caustic potash is made, in every gallon of which, by the aid of as much orpiment, twelve or sixteen ounces of good indigo is dissolved. This solution, when clear, is thickened with gum. This being printed upon the cloth, nothing more is necessary than to wash it when dry.

For Prussian blue. The same mordant is used as for black; but, after cleansing, the piece is winced in a solution of prussiate of potash, in which the prussic acid has been set free by means of sulphuric acid.

For gold. Five pounds sulphate of iron and one pound and a half acetate of lead are dissolved in a gallon of water: the solution, thickened with gum, is printed on the cloth; and, after eight or ten days' age, is winced in a solution of potash made thick with lime. As soon as the black oxide of iron, which is precipitated, commences to redden, the piece is removed to a vessel of water, and then washed.

2. A second, and sometimes third color, is grounded or printed in with a small block, generally after the first has been dyed.

Bark yellow. A mordant is used, the same as for red. The piece, when slightly dunged, is dyed about an hour with one pound of quercitron bark, the infusion being gradually heated during that time to 130° or 160°.

Berry yellow. A decoction of French, or Turkey, or Persian berries, with half a pound of alum

per gallon, is thickened with flour or gum; and the piece, when dry, is passed through a weak alkaline carbonate, or lime-water.

Verdigris green. A solution of sulphate and acetate of copper is put on cloth, which is then passed through a strong solution of potash, in which some protoxide of arsenic has been dissolved.

Drab. The same mordant as is used for purple. Bark, the dye stuff.

Olive. The chocolate mordant dyed in bark. Both these very much diluted, and thickened with gum.

Buff. A weak acetate of iron is applied, and washed in water.

3. Chintzes. A number of different colors printed upon cloth together, viz. black, red, one or two pale reds, purple, blue, green, and yellow. The black, red, and blue, are the same as in No. 1; the purple as No. 1 thickened with gum; the two pale reds are weaker solutions of alum and acetate of alumina, thickened with gum; the yellow is berry yellow, applied after the other colors are finished; the green is formed by the yellow falling upon the blue; and all the varieties of orange, olive, &c., by its falling upon the pale reds and purple. The dyeing and subsequent bleaching are the same as has been described in No. 1, with madder only.

4. A dark ground discharged.-- When the discharge is printed before the mordant, it consists of concentrated lime juice alone, thickened with gum. The mordant, which is also thickened, is blotched over the whole piece, and dried off it as quickly as possible. When the mordant is applied first it is not thickened,