necessary that the wheels D and E should be placed upon their axis, in such a position that their curvature will correspond with the curvature of the prism and platen. For this purpose the universal-joint R is fitted upon the axis 1, of the wheel, with a round part, that it may turn on it. A piece of metal, r, is fixed fast upon the spindle 1, and has a hole in it for the reception of a tooth s, which is screwed fast upon the universal-joint; then two screws being tapped through the sides of the piece r, press upon the end of s, and by forcing it either way, will adjust the wheel with respect to the platen till they exactly correspond; another similar adjustment may be applied to the upper axis.

The manner of forming the ink and distributing rollers with an elastic substance is worthy of particular notice. Leather stuffed in the manner of a cushion was first used, but did not succeed, because it became indented with the types; but after many trials, a composition of glue, mixed with treacle, was found to answer perfectly. The roller is made of a copper tube, covered with canvass, and placed in a mould, which is a cylindrical metal tube, accurately bored, and oiled withinside; the melted composition is then poured out into the space of the mould, and when cold, the whole is drawn out of it, with the glue adhering to the copper tube, and forming an accurate cylinder without any further trouble. The composition will not harden materially by the exposure to air, nor does it dissolve by the oil contained in the ink. This machine is well adapted to print from stereotype plates, which the universities have adopted for their bibles and prayerbooks.

BRAMAH'S BANK-NOTE PRESS.

8. Ir was formerly the custom in the Bank of England to fill up the number and dates of their notes in writing, till the year 1809, when the machine invented by Mr. Bramah was adopted for this purpose. By this contrivance, the numbers and dates were inserted not only in a more uniform and elegant manner, but the labour was diminished to less than one-sixth of what it was before.

The copper-plates from which the words of the notes are printed, are double; that is, they throw off two notes at à time upon one long piece of paper. This piece of paper, containing two notes, is then put into the machine, which prints upon them the number and dates in such a manner, that the types change to the succeeding number, and that the whole operation is performed without any attention on the

part of the clerk. If one of the notes, for example, is N° 1, No 1, and the other on the same paper No 201, No 201, when these are printed the machine alters itself to N° 2, No 2, and N° 202, N° 202; and in printing these, the types again change to N° 3, N° 3, and No 203, N° 203. The date and the word London are cast in stereotype, and each machine is furnished with one of these for every day in the year, and they of course are changed every day.

The Bank of England has upwards of forty of these machines, the greater part of which are in constant use. It was formerly considered sufficient labour for each clerk to fill up the number twice repeated, and date twice repeated, 400 notes per day; but since the introduction of the machine, one clerk has printed 1,300 double notes, which are equal to 2,600 single ones; for though in the machine the double notes do not require more labour than single ones, yet to fill up the blanks by writing would occupy twice the time.

The mechanism by which this is effected is extremely ingenious, and the principle is not limited to the numbering of notes, but is equally applicable to the purpose of printing any series of numbers which require continual alteration. We have represented one of these machines, which is not, however, precisely the same as those in use, being only a single one, and adapted for printing one note at once; but we have only to suppose it extended to twice the length, and furnished with a double set of types, in order to fit it for printing two notes at the same time.

In fig. 305, a perspective view of this machine will be found, and a section of its parts at fig. 304, in both of which the same letters of reference are employed. A solid piece of mahogany, A A, forms the base of the machine, and to this two iron plates, B B, are screwed, forming the sides of a box, the front of which is removed in fig. 305, to exhibit the interior, and the back is concealed between the mechanism. Across this box an axis, D, is placed, having its pivots fixed into sockets which are fastened in the sides of the frame, as is evident from the figure. This axis carries the tympan E, which gives the pressure to print off the note attached to it by screws; and a lever, F, is also fixed to the axis, by which the operator forces down the tympan. The movable types, in which the principal novelty of the invention consists, are fitted into a series of brass circles, mounted upon an axis G, extending across the centre of the frame. These circles are sufficiently pointed out in the perspective view, by the numerals on the types fixed in them; they are ten in number, arranged in two lots of five each.

Each circle (shown more plainly at I, fig. 304) is divided into eleven parts, and at each a rectangular notch is cut, to receive the types 1, 2, 3, 4, 5, 6, 7, 8, 9, 0 and a blank type. Five of the circles, thus prepared, being placed side by side, upon a fixed axis, G, on which they revolve freely, are sufficient for printing any number less than 100,000; because, as the circles can be turned about on their axis independent of each other,

it is obvious that any combination of the above figures may be produced, by bringing them to the highest point of the circle, which is the situation in which they are to be placed when an impression is to be taken. This will he more easily understood, if we consider that the brass plate which covers the circles is put on its place, as represented in fig. 304, at a. This brass plate has two apertures through it, to receive the two series of types which project up a little above its surface when at the highest. In fig 305, this plate is removed to exhibit the interior mechanism.

The circles are made to revolve by means of wheels, H, upon an axis called the back axis, parallel to the axis of the circles. The end of it is seen at I, fig. 305, projecting through the frame, and it carries three of the wheels H, two of which are at the same distance apart as the two series of figure circles to which they apply; the third wheel is placed at an intermediate distance between the other two, and is acted upon by a catch or pallet b, fig. 304, attached to the axis of the tympan, by means of a joint, in such a manner that it will strike against the highest tooth of the wheel H, and turn it round one tooth. When the handle is lifted up rather beyond the perpendicular, a stop a, fig. 305, upon the axis, meeting a projection a fig. 304, on the cover of the box, prevents it from moving farther; but when the handle is returned down the position of the fig. 304, the pallet, though it again meets the tooth of the wheel, gives way upon its joint, and passes by without moving the wheel. In this manner it will be seen, that every time the handle is pressed down to take an impression, in raising it up again to place a fresh paper upon the tympan, the pallet moves the wheels Ĥ one tooth, and as the teeth of these wheels engage the teeth of the figure circles, a similar motion is communicated to them, bringing a fresh number beneath the tympan, ready for printing.

It is to be observed, that the wheels H are of such a thickness, as to engage only one of the five type circles at once, and their distance from each other is such, that they take the same circle in the one series as they do in the other. Now, by moving the back axis a small quantity endwise, it is obvious that the wheel H can be brought to act upon any of the five circles, or be placed in such a position as to be clear of them all. It is for this purpose that the head I, fig. 305, comes through the frame of the machine; for by means of this the axis can be moved on end, and by proper marks upon it, it may be set to any of the five circles. In these positions it is confined by a semicircular clip, which enters grooves turned round on the axis, and deprives it of longitudinal motion, unless when the clip is raised. This can be done by a nut coming through the back of the frame at K, fig. 304. It has a short lever on the inside of it, which, when the nut is turned round, raises up the clip, and releases the axis while it is set to the required circle, and the clip being let fall into the proper groove, confines it from any farther motion.

In order that all the circles may stop at the exact point, when the figure is at the highest, and consequently when the surface of the figure will be horizontal, an angular notch is made on the inside of the figure circles, in the intermediate spaces between each figure; and at the lowest points of the circle e, fig. 304, a movable pin is fitted into the fixed axis, with a spring, which gives it a continual pressure downwards. The end of the pin is formed spherical, and well polished, so that when the circle is turned round it is forced into its hole in the axis; but when another notch in the circle presents itself, the pin presses out into it, and retains the circle with a moderate force in its proper position, until the raising of the tympan, as before described, overcomes the resistance of the pin, and turns the circle round. By this contrivance the types always arrange themselves into a

straight line, after being turned round, without which the impression would have a very disagreeable and irregular appearance. The tympan E, fig. 304, is composed of two parts; a solid brass plate, against which a few folds of cloth are placed and secured by the second part, which is a brass frame covered with parchment, and attached to the former by four screws, two of which appear at ff, in fig. 305.

The brass plate of the tympan is fastened to the leaf L, fig. 304, projecting from the axis by means of six screws. Two of these, only one of which, h, can be seen in the figure, tend to throw the tympan from the leaf; while the other four, which are arranged one on each side as the two former, draw the tympan in and leaf together. By means of these screws thus acting in opposition, the tympan can be adjusted so as to fall exactly parallel upon the type, and communicate an equal pressure to all parts of the paper, which is held against the tympan by means of a frisket of parchment stretched on a frame which surrounds the tympan, and is movable on joints at k k, fig. 305. The frisket is cut through as is represented by the shaded parts in fig. 305, in order to expose the paper where it is to receive the impression of the figures, and the No. before the figures, and also the impression of the date, year, and place. The type for these are formed in stereotype, and fastened down upon the surface of the brass cover a, the piece containing the day and month being changed every day. In order to find the proper position which the paper should occupy upon the tympan, two fine pins are fixed to project from it, and are received into holes made in the brass cover; two dots are printed upon the note from the copperplates, and the pins being put through at these dots, ensure the figures, &c. coming on their proper places.

The manner of using the machine is as follows: suppose the back axis put so far on end as to be detached from all the circles; the figure circles arranged by hand, so that the blanks are all uppermost; and the proper stereotypes put in for the date. The back axis is then first set, so that its wheels H may take the first five circles towards the right hand, and by moving the handle down almost to touch the type, and returning it up again, the pallet moves the wheels H, and turns the two right-hand circles, bringing up figure 1. The clerk now inks the type with a printer's ball, opens the frisket sheet L, fig. 305, on its hinges, and places the note (already printed on the copper-plate press) against the tympan, the proper place being determined by the two pins, and the dots printed on the note, as before mentioned. He now shuts up the frisket sheet, in order to confine the paper and keep it clean, except in the places where it is to be printed; then by pressing down the handle F, the impression is given; and on lifting it up again it moves the circles and brings up figure 2. The note is now removed, a fresh one put in, and so on, the figure always changing every time.

During this operation the two right-hand circles act as units, and advance one each time; when 9 are printed in this manner and 0 comes up, the handle is moved twice successively without printing, which brings up a blank and then a 1. The back axis is moved, to act upon the second circle upon the right hand, which now becomes the units, the first circle representing tens; by moving the handle a, without printing, figure 1 in the second circle comes up, making 11, the next time 12, and so on to 19. The first circle is now put forwards by hand, bringing up 2 and 0, on the second 20, then moving the handle to pass the blank, produces 21, 22, &c. to 30, when the first circle is again advanced, bringing up 4; in this manner the business proceeds to 99. The back axis is now shifted to the third circle, which be zomes units, the second tens, and the third hundreds; the 0 and blank of

which are advanced to bring up 1, 0 is brought up in the second; and the machine itself brings up 0 in the third; after printing this it changes to 101.

The process now continues through the successive hundreds in the same manner as before till 999. The back axis is now shifted to the fourth circle, and the three first must be advanced by hand when they require it. At 9999 the back axis is shifted to the fifth circle, and it will serve to 999,999, beyond which it is not required to print.

PILE-ENGINE.

THE pile-engine is a machine by which piles are driven into the ground for the foundation of the piers of bridges, and various other structures.

The method of driving a pile consists in drawing up a very heavy weight, called a ram or hammer, and by disengaging it from the machinery by which it was raised, letting it fall, by the force of gravity, upon the head of the pile. In the most simple machines the weight is drawn up by men pulling a cord over a fixed pulley, and when it has attained a sufficient height allowing the cord to slip from their hands, which permits the weight to descend with considerable force. The two best pile-engines that we have seen are those invented by Mr. Vauloué and Mr. S. Bunce,

Mr. Vauloué's pile-engine may be thus described. A, fig. 306, is a great upright shaft or axle, on which are the great wheel B, and the drum C, turned by horses joined to the bars S S. The wheel B turns the trundle X, on the top of whose axis is the fly O, which serves to regulate the motion, as well as to act against the horses, and to keep them from falling, when the heavy ram Q is discharged to drive the pile P down into the mud in the bottom of the river. The drum C is loose upon the shaft A, but is locked to the wheel, B, by the bolt Y. On this drum the great rope, H H, is wound; one end of the rope being fixed to the drum, and the other to the follower G, to which it is conveyed by the pulleys I and K. In the fol lower G is contained the tongs F, that take hold of the ram Q, by the staple R, for drawing it up. D is a spiral or fusee fixed to the drum, on which is wound the small rope, T, that goes over the pulley U, under the pulley V, and is fastened to the top of the frame at 7. To the pulley block Vis hung the counterpoise W, which hinders the follower G from accelerating as it goes down to take hold of the ram; for, as the follower tend's to acquire velocity in its descent, the line T winds downwards upon the fusee upon a larger and larger radius, by which means the counterpoise, W, acts stronger and stronger against it; and so allows it to come down with only a moderate and uniform velocity. The bolt Y locks the drum to the great wheel, being pushed upward by the small lever 2, which goes through a mortise in the shaft A, turns upon a pin in the bar 3, fixed to the great wheel B, and has a weight 4, which always tends to push up the bolt Y, through the wheel into the drum. Lis the great lever turning on the axis m, and resting on the forcing bar 5, 5, which goes through a hollow in the shaft A, and bears up the little lever 2.

By the horses going round, the great rope H is-wound about the drum C,