[342]
[343]

OF
AN ADDING MACHINE,
Or Machine to Cast up large Columns of Figures.

This Machine is not, generally, an arithmetical Machine. It points lower: and therefore promises more general utility. Though less comprehensive than machines which perform all the rules of arithmetic, it is thought capable of taking a prominent place in the counting-house, and there of effecting two useful purposes—to secure correctness; and thus, in many cases, to banish contention. It is represented in figs. 1, 2, 3, and 4 of Plate 42, and in figs. 3 and 4 of Plate 43.

There are two distinct classes of operations which may be noticed in this Machine: the one that does the addition, properly speaking; and the other that records it by figures, in the very terms of common arithmetic. The first operation is the adding: which is performed by means of an endless geering chain, stretched round the wheels A B C D, (fig. 1) and over the two rows of smaller pulleys a b c d e f g h i; where, observe, that the chain is bent round the pulley A, merely to shorten the Machine, as otherwise the keys 1 2 3, &c. to 9, might have been placed in a straight line, and thus the bending of the chain have been avoided.

The chain, as before observed, geers in the wheels B and D, which both have ratchets to make them turn one way only. Now, the keys 1 2, &c. have pulleys at their lower ends, which press on the aforesaid chain more or less according to the number it is to produce, and the depth to which it is suffered to go by the bed on which the keys rest, when pressed down with the fingers. Thus, if the key 1 be pressed, as low as it can go, it will bend the chain enough to draw the wheel B round one tooth—which the catch E will secure, and which the wheel C will permit it to do by the spring F giving way. But when the key 1 is suffered to rise again, this spring F will tighten the chain by drawing it round the pulleys A and D, thus giving it a circulating motion, more or less rapid, according to the number of the key pressed. Thus, the key 5 would carry five teeth of the wheel B to the left; and the catch E would fix the wheel B in this new position: after which the spring T would tighten the chain in the same direction and manner as before. It is thus evident, that which-ever key is pressed down, a given number of teeth in the wheel B, will be taken and secured by the catch E; and, afterwards, the chain be again stretched by the spring F. It may be remarked, that, in the figure, all the keys are supposed pressed down: so as to turn the wheel B, a number of teeth equal to the sum of the digits 1, 2, 3—to 9. But this is merely supposed to shew the increasing deflexion of the chain, as the digits increase: for the fact can hardly ever occur. We draw from it, however, one piece of knowledge—which is, that should the eye, in computing, catch several numbers at once on the page, the fingers may impress them at once on the keys and chain; when the result will be the same as though performed in due succession.

Thus then, the process of adding, is reduced to that of touching (and pressing as low as possible) a series of keys, which are marked with the names of the several digits, and each of which is sure to affect the result according to it’s real value: And this seems all that need be observed in the description of this process. It remains, however, to describe the 5th. figure, which is an elevation of the edge of the keyboard, intended to shew the manner in which the two rows of keys are combined and brought to a convenient distance, for the purpose of being easily fingered.

We now come to the other part of the subject—that of recording the several effects before-mentioned. The principle feature in this part, is the System of carrying, or transferring to a new place of figures, the results obtained at any given one. This operation depends on the effect we can produce by one wheel on another, placed near it, on the same pin; and on the possibility of affecting the second, much less than the first is affected: Thus, in fig. 3 and 4, (Plate 42,) if A be any tooth of one such wheel, placed out of the plane of the pinion B, it will, in turning, produce no effect upon that pinion: but if we drive a pin (a) into the tooth A, that pin will move the pinion B one tooth (and no more) every time this pin passes from a to b. And if we now place a second wheel (F) similar to A, at a small distance from it, so as to geer in all the teeth of the pinion B, this latter wheel will be turned a space equal to one tooth, every time the pin a passes the line of the centres of the wheel and pinion A B, (say from a to b.) It may be added, likewise, that this motion, of one tooth, is assured by the instrument shewn at E D, which is called in French a tout ou rien, (signifying all or nothing) and which, as soon as the given motion is half performed, is sure to effect the rest: and thus does this part of the process acquire, likewise, a great degree of certainty—if indeed, certainty admits of comparison.

It is then, easy to perceive, how this effect on the different places of figures is produced: and it is clear, that with the chain motion just described, it forms the basis of the whole Machine. There is, however, one other process to be mentioned, and as the 2d. figure is before us, we shall now advert to it. In adding up large sums, we have sometimes to work on the tens, sometimes on the hundreds; which mutations are thus performed: The wheel B, (fig. 2) is the same as that B, fig. 1; and it turns the square shaft B G, on which the wheels k l slide. The wheel l is to our present purpose. It is now opposite the place of shillings; but by the slide m, it can be successively placed opposite pounds, tens, hundreds, &c. at pleasure: on either of which columns, therefore, we can operate by the chain first described—the wheel B being the common mover.

We shall now turn to figs. 3 and 4 of Plate 43, which give another representation of the carrying-mechanism, adapted especially to the anomalous carriages of 4, 12, and 20, in reference to farthings, pence, shillings, and pounds, and then following the decuple ratio.

In fig. 3, k l represent the two acting wheels of the shaft B G, fig. 2; the latter dotted, as being placed behind the former; these wheels, however, are not our present object, but rather the carrying system before alluded to; and described separately, in fig. 3 of Plate 42. A, in figures 3 and 4 (of Plate 43) is the first wheel of this series. It has 12 teeth with three carriage-pins (or plates) a, which jog the carrying-pinion B, at every passage of 4 teeth; thus shewing every penny that is accumulated by the farthings. This is so, because the farthings are marked on the teeth of this first wheel in this order—1, 2, 3, 0; 1, 2, 3, &c. and it is in passing from 3 to 0, that this wheel, by the carriage-pinion B, jogs forward the pence wheel C one tooth: But this pence wheel is divided into 12 numbers, from 0 to 11; and has on it only one carrying-pin (or plate) b; so that, here, there is no effect produced on the third wheel D, until 12 pence have been brought to this second wheel C, by the first, or farthing wheel A. Now, this third wheel D, is marked, on it’s twenty teeth, with the figures 0 to 19, and makes, therefore, one revolution, then only, when there have been twenty shillings impressed upon it by twenty jogs of the carriage-pin b, in the second wheel C. But when this wheel D has made one whole revolution, it’s single carriage-pin c, acting on the small carriage-pinion, like that c d, (but not shewn) jogs forward, by one tooth, the wheel E, which expresses pounds; and having two carriage-pins e f, turns the wheel called tens of pounds, one tooth for every half turn of this wheel E: and as, on all the succeeding wheels, to the left from E—(see fig. 2, Plate 42) there are two sets of digits up to 10, and two carriage-pins; the decuple ratio now continues without any change: and thus can we cast up sums consisting of pounds, shillings, pence, and farthings, expressing the results, in a row of figures, exactly as they would be written by an accountant. The opening, through which they would appear, being shewn in fig. 1, at the point w, corresponding with the line x y of fig. 2 in the same Plate.

I shall only remark, further, that the figures 3 and 4 in Plate 43, are of the natural size, founded, indeed, on the use of a chain that I think too large; being, in a word, the real chain de Vaucanson, mentioned in a former article: and that the figures of Plate 42 are made to half these dimensions, in order to bring them into a convenient compass on the Plate.

I would just repeat, that I have not attempted here an arithmetical machine in general; but a Machine fit for the daily operations of the counting-house; by which to favour the thinking faculty, by easing it of this ungrateful and uncertain labour. Had I been thus minded, I could have gone further, in a road which has been already travelled by my noble friend the late Earl Stanhope, (then Lord Mahon) but I took a lower aim; intending in the words of Bacon—“to come home to men’s business and bosoms.”

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OF
A ROTATORY PUNCH MACHINE
Adapted to my own Engraving Machine.

It is highly desirable, (not to say indispensable) in the use of my engraving Machine, to have punches not only of the true cylindrical form, but exactly of the proper length. (See the remarks on this subject, in the description of that Machine). It is, therefore, a matter of consequence, to be assured that both these circumstances unite; and to unite them without depending on personal skill, whenever the work can be accomplished without such dependence: and this is the object of the present rotatory Punch Machine. Adverting first to the length of the punch: that is insured by having a kind of slide on the Punch Machine, formed like the frog spoken of in the above article—Engraving Machine. In the 5th. figure of Plate 43, this slide is shewn at a, and it is at exactly the same distance from the centre of motion A, as the bottom of the frog-plate fig. 3 Plate 39 is from it’s centre of motion. Thus, the bottom of the punch is filed straight, once for all, and being fixed in proper clams, as in the figures, the shaft A is set a-turning, by power—from which motion two uses are derived: first, the cylindrical form is given to the punch by presenting to it, in it’s revolution, a file duly wedged on the (now fixed) slide of the Machine B B; against which it is kept turning, till, by a due depression of the centre A, the radius is brought to the length required, and the surface perfectly formed and smoothed. This being achieved, the cams c d, are fixed to the slide B B, and to the turning body A d, so that when the die f is moved toward the left hand by the said cams, the prepared punch gently presses on it, and begins to receive it’s impressions; which are gradually deepened by the set screws g h, fig. 6; till, at once, the proper radius is given, and the engraving sufficiently transferred from the die to the punch—an operation which this process is calculated to perform, rather by means of frequent and gentle contacts, than by slow and heavy pressure. It need not be added, that the motion of the slide B B is reciprocated by the spring C, against that D, after each forward motion given to it—as begun by the cams c d, and continued by the contact of the die and punch, all which a mere inspection of the figures will sufficiently explain. It is likewise evident, that the figs. 5 and 6, shew, both, the same objects, namely:—the regulating wedges i k, the upper set screws g h, and the rollers E, on which the slide vibrates during the operation of the Machine.

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OF
A PORTABLE PUMP,
To be worked by the Feet.

It is not solely because, to work with the feet is a good method of employing the strength of men, that this device is presented to the mechanical public; but it is with the view of so employing the feet and hands, that they may occasion a constant and equable flow of water. The means, (see Plate 44, fig. 1) are, to provide the man with two supports a b for his hands, and two pedals c d for his feet, by which the two rods e f are worked; and by them, through the cords or chains g h, the piston rods i and k. Of the latter, the one which answers to the lower pump l, goes through the upper piston, whose rod is i: and the pistons are both constructed in the manner shewn in fig. 2; that is to say, the piston has no body, fitting the pump barrel: but a triangular bar x, going diagonally across the pump barrel, (which is square) and carrying two wings or valves y z; which, both together, fill the barrel when down, and leave it as empty as possible when up, by which motion the chains a e are slackened. Further, these pistons, with their rods, are heavy enough to raise the pedals, the instant the man raises his feet in any degree: so that, by a proper combination of the motions of his hands and feet, he can let down a given piston, and begin again it’s ascending motion before his effort has wholly ceased on the other pedal. A mean this, of producing a constant and equable rising motion in the column of water through the pumps k l; and a mean also, of doing more work with a given fatigue, than would be possible in a pump whose motions were merely reciprocal, and the water of which, in rising, would be subject to any unequable or convulsive motions.

In general, this portable pump was made (many years ago) with a view to being easily carried to any field or garden, bordering on a river, and worked on it’s bank; the flexible suction pipe p being thrown into the river, or a well, as occasion might require. To this end, the whole frame (as is evident from the figure) can be folded up into a kind of faggot: and thus it’s transport from place to place, be made perfectly commodious.

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OF
THE BISECTING COMPASSES.

It often happens, that from a central line, (in drawing for example) we want to set off, quickly, many equal distances on each side; or between two given lines we want a central line; to perform either of which operations, is the use of the Instrument just mentioned.

It is represented in Plate 44. figs. 3 and 4, where A B is the central point, being cylindrical in the greatest part of it’s length, and conical at E B. It slides correctly in two cannons or swivels E & A, which also have two short axes or trunnions, on which first, the double compass joints C D turn; and second, the two pairs of arms F G. I have called these cannons, swivels, that I may shew their construction, by referring to figure 1 in Plate 30—which describes the swivel of the forcing Machine; and which will give a complete idea of what is here intended. From this construction it will appear evident, that the point A B, (Plate 44) will be always found in the middle, between the two points, of the outer legs of the compasses; and that whether the question is to take two equal distances from a central point, or to bisect a given line or distance at one operation. The point or style now slides in the two swivels A and E; but the Instrument might be so constructed, as for it to follow the rising motion of the middle joint (E), and thus to keep the three joints in the same horizontal line: but I think a small perpendicular motion of the said style, would be always desirable in the Machine, as a drawing Instrument.

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OF
A MUSICIAN’S PITCH-FORK,
With variable Tones.

This device is shewn, in two positions, at figs. 1 and 2 of Plate 45. In it’s present application, it is intended to produce a whole octave on the diatonic scale: and therefore, the unsupported ends of the fork are just half as long as they would become if the sliding handle A, were drawn to the bottom end of the branches c d. For, again, the fixing screw C, and it’s box D are fastened to this sliding handle by one or two screws, (s) so as to be always ready to press the branches against the enclosed slide A B, at whatever place the intended tone may be found. Now, the branches a c, b d, spring out of a common trunk c d, which is pierced with a square hole, exactly fitting this sliding handle A B; and the latter is marked, at proper distances, with lines across it, each of which (placed opposite the mark c d) gives such a length to the remaining branches a b, as to make them sound the note desired. Thus, the line l, brought to c d, lengthens the branches a b, to (nearly) 53 parts, from 50 at which they are now fixed; the whole length a c, being 100. This, and the following divisions would, of course, follow any desired temperament, according to the will of the tuner: but I have supposed them founded on the equi-harmonic scale; and thus will the successive intervals to be set off on the slide B A, be as follows: (while the corresponding notes will be those expressed in the table.)

In the state represented by the figures 1 and 2, the line a B, is 5000; being one half of the whole length a b, c d.

To form the	Sharp	7th.	it becomes	5297	the distance	c d 1,	being	297.
„	greater	6th.	„	5946	„	1-2,	„	649.
„	„	5th.	„	6674	„	2-3,	„	728.
„	„	4th.	„	7491	„	3-4,	„	817.
„	„	3rd.	„	7937	„	4-5,	„	446.
„	„	2nd.	„	8909	„	5-6,	„	972.
„	fundamental note			10000	„	6-7,	„	1091.

The above lengths 1 2, 2 3, &c. have been measured off on the slide A B, as nearly as possible, or at least with precision enough to give the idea: and the rest I must leave the detail of, to those musical readers who may feel interested in the subject.

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OF
AN ESSAY,
To obtain a Level at Sea.

I have done right in calling these attempts “essays”: and if I had said “immature attempts,” they would have been better designated. Yet, having promised them to my readers, I cannot now withhold them, although, from want of opportunity of trial, I can do little more than talk of their supposed properties.

The first essay, as shewn in fig. 3 of Plate 45, is a mental deduction from a device which I executed in 1801, and brought before the public at the exhibition then given, by the French government, of the produce of national industrie. It was, nothing more than a pendulum, made with a view to lengthen, considerably, the going of a given clock, without altering the wheels. To that end, the weight or bob, was a heavy bar C D, suspended diagonally on two points A B, placed at a distance from each other, exactly equal to the length of the said bar: and that by the double cross-bars B C and A D, of a length sufficient to make the whole assume a form exactly square: where it may be noted—that were this figure longer than high, the curve of vibration would have two points of inflexion, and the bar would not place itself horizontally at last; and that were it narrower and higher, that curve would assume a form more like, though still distant from, the arc of a circle. In the present case, such was the effect of this disposition of things, that the centre of gravity of the bar described, in vibrating, a curve E C D F, the lower form of which, was so near to a horizontal line, that the times of vibration were immensely prolonged; so much indeed, as to represent a common pendulum of several thousand feet in height; and to give a proportionate slowness to any mechanism with which it should have been connected. In fact, this line is so minutely different from such horizontal line, that it is wholly included in the thickness of the drawn-line C D: nor becomes visible but near it’s two ends C D, when it begins to rise, and then rises faster than that described by a short common pendulum.

In fine, this curve itself is formed by continually bisecting the line or bar C D, and drawing lines from it’s centre of gravity, thus found in one of it’s positions, to the same in another position, till the curve E C D, &c. arises from this process.

It follows, then, from the nature of this curve, (or pair of curves) that the time of vibration of this pendulum is the longer, the shorter the arcs are, in which it vibrates; and that, when the vibrations have attained a certain length, compared with the height to which the centre of gravity rises, the time becomes considerably shorter. I shall not now pursue this idea, because it is at once an abstruse question, and at the same time one of uncertain utility—I mean that it’s use is problematical as a pendulum: since the time of a vibration depends on it’s length, which cannot easily be determined by any invariable method. I shall, however, add two things on this subject, by way of land mark; the one, that the balance-wheel of a watch has power enough to drive this pendulum, heavy as it is;—and the other, that I have seen it make (for many hours together) vibrations of half a minute’s duration! In a word, this is one of the subjects, which untoward circumstances have prevented me from bringing to maturity—but which I owe to my subscribers, and the public, in any, or every state, to which I have brought them.

I therefore, say nothing more of this Instrument as a pendulum: but an inspection of the figure will shew, that it will not be useless as an Elipsograph—which it clearly is, since the intersection of the bars A D & B C; describes a true Ellipsis. It may be further shewn, that the ends of the moveable bar C D, are the vibrating foci of a second ellipsis, like the first, which rolls under the other, so that the curve itself is that which the centre of one ellipsis a b c would describe, by rolling on the surface of another e b d. But, into these considerations I cannot now enter, as my “Century of Inventions” is fast becoming due, and time commands dispatch; I beg leave, therefore, to pass to the relation this subject seems to bear to a “Marine Level.”

It must, however, be premised, that I scarcely expect either of these methods to be correct enough for astronomical observations; as among other things, they have the nautical top to contend with: but if I am fortunate enough to have suggested useful methods of procuring relative stability on board a rolling ship, so as to suspend the better, a nice instrument of astronomy; or so to counteract the restless ocean, as to assist the victims of sea-sickness, I shall not entirely have lost my labour.

My first idea on this subject, is the following: If we had on ship-board, a simple pendulum of several thousand feet high, it appears certain that the oscillations of the ship would be begun and ended, before any single vibration could have been given to such a length of pendulum—which therefore, would scarcely vibrate at all: and if the natural time of this compound pendulum (for we are not confined to these small dimensions) were made to be much longer than those of the ship on it’s meta-centre, this pendulum would scarcely vibrate at all: because it’s several tendencies to take motion from the ship, would extinguish each other before they had had time to produce any common effect.

Further, this result would probably be assisted by another property belonging to this mechanism: see fig. 4. This diagonal suspension, as repeated at a b c d, fig. 4, is of such a nature, that when it’s centres a b, are placed in any oblique position e f, (say by the rolling of a ship) the suspended bar c d, immediately takes a position of opposite obliquity g h, pointing upward towards i, just as much as the line e b points downward; while the middle line k l remains level—whether caused by the slides k l, or the single slide m.

I dare not assert any thing respecting the form this principle should assume, in order to produce the most useful effects; but it appears that the principal weight of the apparatus should be placed in the centre of gravity of the under bar c d. It would occur, of course, to every mechanician applying this System to real use, that in this fig. 4, we have only provided for one motion of the ship, the rolling motion: and that, in consequence, this System should be suspended in another similar one, acting longitudinally, so as to provide for the pitching motions of the vessel. In a word, I confess, with regret, that I leave much to do, by way of bringing this idea to maturity—it being at this late hour, more than doubtful, whether I shall myself ever be able to resume the subject at sea, where alone it can be duly tried.

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OF
A SECOND ESSAY,
To procure a Marine Level.

This would seem to be a simpler process than the former: but how far it may go beyond it in effect, I cannot say—having never had it in my power to try either of these ideas on ship-board. I therefore merely present them to my readers, as themes for future thought and experiment.

Plate 45, fig. 5 represents this System—which is founded on the idea of deadening oscillatory motions at sea, by connecting the bodies to be thus guarded, with a stream of flowing liquid, the horizontal motions of which must be subject to laws very different from those which rule vibrating bodies merely suspended.

The fluid used in this Machine (as oil, water, mercury, &c.) is to be pumped up by appropriate mechanism, from the vessel into which it flows at x, into a vessel placed a little above z; and to be let out by the cock y, through a kind of strainer s, of sufficient collective area to supply, with ease, the descending column C. The vessel and tube C D are made as thin and light as possible: and the upper part, which is spherical, is inclosed in and suspended by the universal joint a b c, like those used to suspend other bodies, as a compass, &c. Moreover, the areas, at different heights, of the tube C D, are made in the inverse ratio of the velocities of the spouting fluid, at each given depth—so as to leave it but little tendency to press either outward or inward, while thus obeying the law of gravity. By these means, then, I think no vibrating motion will be excited in the falling column: but that the liquid will continue to flow perpendicularly, so as to preserve (nearly) the quietude of the vessel C D, and of any mirror or instrument it may be wished to keep in a given position, by connecting it with the perpendicular line thus obtained.

I repeat, however, that I know not how far these methods may go towards obtaining an artificial horizon, for astronomical uses. Indeed, I fear they will fall short in this respect—but I think them still worth trying, even for these—but especially for the purposes to which I have already alluded. And, if success crowns this publication, to the degree I am led to anticipate, I will not always leave so rich a question, in this doubtful predicament.

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OF
A FIRE-ESCAPE,
On a retarding Principle.

This is a recollection from the specification of a Patent which I took out above thirty years ago, and in which I huddled together as many objects as a child would like to see in a box of play things. I perhaps acted, then, according to the words of a French proverb—“abondance de bien ne nuit pas;” but in so doing, I fell into the charybdis of another French proverb—“qui trop embrasse, mal Étreint,” (a wide embrace cannot be a strong one) and in so doing, paved the way to much litigation—which happily did not occur.

The intention of this Machine, as represented in Plate 46, fig. 2, was to retard the fall of any body, or person, suspended to it, so as to prevent any concussion on reaching the ground. The means are brought to view in the perspective sketch given of the Machine. It is a kind of jack, inclosed in a case, and supposed to be laid carefully aside in the house represented in fig. 1 of this Plate. The Machine has a barrel, much like that of the jacks used for roasting; round which a rope is coiled, of sufficient length to reach the ground: and a wheel, connected with this barrel, works in an endless screw, which turns a shaft also like that of a common jack, but somewhat stronger; and finally, to this shaft is fixed a small cross piece, carrying, on pins, two weights y z, inclosed in the fixed barrel x; by the centrifugal force of which enough friction is created, to prevent the acceleration of the falling body—whether a person or weight of any kind.

There is, moreover, a jib a, fig. 1, fixed between some, or all, the windows of the house whose inhabitants it is wished to guard from the danger of fire; this jib having the property, from the form of it’s foot, of taking by the suspension of any weight to it, a position perpendicular to the wall: Insomuch, that by the act of suspending the Machine to the jib—engaging the wrist in the noose n, and perhaps the foot in another loop of the same cord; a person may safely flee those dangers from fire, of which so many persons become the unhappy victims.

Since the 46th. Plate was engraved, it has occurred to me, that a method should have been shewn for raising the cord n, (fig. 2) after each descent. This operation might be performed by a handle put on the axis of the Machine, accompanied by a ratchet on the wheel, just like the similar parts of a jack for roasting. But, lest the inmates of a house on fire, should not have presence of mind enough to perform this operation, it might be better to have a spiral spring in the Machine, to be wound up by the descending body, and of force sufficient to raise again the cord after such descent.

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OF
A SECOND FIRE-ESCAPE,
By breaking the Fall.

This Machine is also shewn in Plate 46, at fig. 1. It consists of a large truck, A, to be drawn rapidly to any house on fire, by one or more horses. The carriage or frame part B B, is an open square frame subtended by a first sheet of sack cloth, similar to the sacking of a bed: and on this are laid five, or more, air mattrasses made of sack cloth, and varnished on the inside so as to be nearly air-tight; I say nearly so, for it is not intended they should form a spring capable of returning any object thrown on them. On the contrary, each of the mattrasses has, at one or both ends, a valve 1, 2, &c. opening outwards, but kept closed by proper springs, so as to determine the pressure at which the air shall escape; that pressure being carefully graduated, so that the upper mattrass shall give way with ease, the second with greater effort, and the successive ones with progressive difficulty, until the under one remains totally closed, and stops the falling body altogether. By these means, if enough mattrasses are used, and they are duly regulated, a person may jump from a house of three or four stories without incurring any danger. As to the length and breadth of this fire-escape, it should be ample enough to give the sufferers confidence to take the leap, and as small as an easy passage in the principal streets would require.

One thing must be described in words—as the mechanism to which it relates is fixed under the truck; and could not be seen in this perspective figure. These mattrasses are filled with air by an horizontal air pump, worked by a crank, which the axle itself of the hind wheels of the truck forms: whence, by pinning this axle to either of the hind wheels, the very motion of the carriage, as drawn by the horses, would distend the mattrasses—which would thus be ready for use the moment they arrived on the spot; and moreover, when there, this air could be replenished, after using, by turning this axle, through the wheels, by hand cranks slipped on it’s ends at the place of the linch-pins. Or, in fine, this operation might be performed by an air pump prepared for it alone, and placed in any convenient part of the Machine.

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OF
A ROTATORY CHOCOLATE MILL.

Figures 1 & 2 of Plate 47, exhibit this Machine. It is, merely, an attempt to effect, by power and a rotatory motion, what is done by hand and a vibrating one. To understand this latter, my readers (who have not seen chocolate made) will suppose a metallic rolling-pin, but cylindrical held in both hands, and moved parallel to itself, over a slab of marble, to and from the person employed; who holds the instrument fast when pushing it from him, and suffers it to turn a little every time he draws it towards him. He thus presents, sometime or other, every particle of the chocolate to every part of the slab and the roller: and this is also done by the Machine shewn in Plate 47. In figs. 1 and 2, A represents a cylinder of stone or metal, used instead of the aforesaid slab; and B a cylinder answering to the roller in question. The latter is placed, by it’s axis, on two forks a b, so as to lean, by it’s weight, obliquely against the cylinder A, which it does less or more heavily as the forks, or stands a b, are placed nearer or farther off from the general centre. Further, the motions of these two rollers A and B, are connected by two equal (or nearly equal) wheels c d, by which, when A is turned, B turns also; but so as to give the surface of the latter much less velocity than that of A, though in the same direction. By these means, all the matter adhering to both cylinders (for chocolate is made in an unctuous state) is at one time or another, brought into intimate union, and ground together; and thus is the usual problem resolved, on rotatory principles: nor need we mention the several scrapers, &c. that would be applied to gather up the paste to the middle of the rollers, when spread abroad by the grinding process.

It may not be useless, just to say here, that this is likewise a good mill for grinding paint or oil colours.

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OF
A ROTATORY MANGLE.

I have insisted, often, on the propriety, mechanically speaking, of doing every thing by rotatory motion; and thus of avoiding oscillation wherever it is possible. The present Mangle is another attempt to employ that principle. In Plate 47, figs. 3 and 4, is an under cylinder, turned as usual by any convenient power. B is a small cylinder not connected with it, nor touching it, being intended merely to receive the weight of the mangle-cylinder D, with the goods rolled on it. C is an upper cylinder as heavy as necessary, or loaden through it’s journals or centres, with sufficient weights to make it so. Again, the motions of the two cylinders A and C, take place in such a direction, that any round body placed and pressed between them, would receive from them the same motion; and thus, a roller of goods, there introduced, will be mangled. This process is so performed, because the cylinders have toothed wheels a, b, on their axes, but which do not geer together: These wheels being connected by an intermediate wheel c, which makes them concur in producing the rolling effect above mentioned. But, one thing remains to be observed: the wheels a b, though drawn apparently equal, are not equal. The upper one a, has a tooth or two more than the under—so that the motion to the right hand of the under surface of that cylinder, is not equal to the opposite motion of the cylinder A. And hence, the cloth roller D, progresses from D towards x, between the cylinders A C, and finally falls out at x, after as many turns of the whole, as the wheels A C have been calculated to give; and this, is according to the degree of mangling required.

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OF
A MACHINE,
For driving the Shuttle of Power Looms.

It is too late to bring this Machine into what might almost be called an overstocked market of ingenuity—since many power Looms exist, work, and seem to want nothing to make them perfect. But an idea of forty years standing, founded on a principle worthy of attention then, may perhaps not be altogether vain at present: Besides—I have engaged in my prospectus to present it to the public. I could, indeed, enter into other parts of the Power Loom—which I had then begun to execute; but such is the rapidity with which that Machine is now striding to perfection, that it would be superfluous. I merely then, fulfil my promise.

On the afore-mentioned occasion, I thought it of importance, that the force employed to throw the shuttle, should be capable of being regulated to any and every degree: and especially should be fully prepared to act, before it’s action began: and should, then, act independently of every other impulse.

In fig. 1 of Plate 48, A is a wheel or pulley of about six inches in diameter, from which two cords proceed in opposite directions (B C) to the pickers, which drive the shuttles D E in the usual method. This pulley runs on an axis going through the bottom of the lathe, (or beater) and it might have a crank, behind, of a radius equal to a b: but to shew the whole in one figure, I suppose the following mechanism to be placed in the front of the lathe, and just before the face of this wheel or pulley A. c d is a bar turning on the centre c, and receiving at it’s other end the pressure of a spring e d, which in it’s turn, is susceptible of different degrees of springiness, as regulated by the screw f. On a stud i in the wheel A, is put the small bar i d, which forms also a turning joint in the bar c d: and thus communicates the effort of the spring to the stud i, and thence to the wheel A. Finally, this wheel has either under it, on the front side of the lathe, or on it’s axis, at the back, a pulley, by which it can be turned, by means of one or other of the cords brought from the breast beam of the loom, round the pullies x and y, to this wheel a b i, according to the dotted lines. Supposing then, one of these cords to be tightened by the backward motion of the lathe, it will draw the wheel A about half round: when the stud i will rise to the point b, straining the spring to get over the centre: and as soon as it is over, the spring will act, and drive the picker and the shuttle with the desired speed, independently of any other mover. And it is evident, that now the opposite cord x or y, will be tightened so that when the lathe shall be again pushed backward to form the opening for the shuttle the slide will be carried back over the centre a, and re-produce another impulse in a contrary direction.

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OF
AN AIR PUMP,
Or Essay towards completing the Vacuum.

The rapidity with which a vacuum is formed by an Air Pump, depends on the ratio between the contents of the receiver and those of the pump barrels. If the latter be just equal to the contents of the former, (which is a very large proportion) the exhaustion will follow this series:—there will remain in the receiver after each stroke, the first contents being 1, ¹/₂, ¹/₄, ¹/₈, ¹/₁₆, ¹/₃₂, ¹/₆₄, ¹/₁₂₈, ¹/₂₅₆, &c. But if the pump barrel contains twice the volume of the receiver—then the remaining air, after the strokes, will be ¹/₃, ¹/₉, ¹/₂₇, ¹/₈₁, ¹/₂₄₃, ¹/₇₂₉, ¹/₂₁₈₇, ¹/₆₅₆₁, &c. being much nearer to a vacuum than on the former supposition.

To meet this case, then, I have thought a water pump might be used: that is, a barrel or vessel, much larger than the receiver; and which by the action of a smaller pump, placed on a lower level, might be alternately filled with water and emptied so as in a few operations to complete the exhaustion, very nearly.

Thus, in fig. 2 of Plate 48, A is a receiver, B is a large vessel that can be filled with water from the tub C below; and D is the pump, worked by the handle E. It is a common water pump, (so much the readier adopted, as requiring little care in the execution.) The question was to make this pump alternately fill and empty the vessel B. Adverting first to the filling, a c are two cocks, having each a side-passage for the water; and these passages are now so placed, as by working the pump we suck water out of the tub C, and throw it into the vessel B, through the valve b;—by which means all its air is driven out through the lateral valve e. When this is done, the cocks c d (which are so made as to be worked by the same mover) are turned into a new position, which opens the pipe p to the pump D, and that q to the returning spout r; by which means the water is drawn from the vessel B, and thrown into the tub C: so that the air is again drawn out of the receiver A, through the inverted valve s, into the vessel B, and another degree of exhaustion occasioned. This being done, the cocks are again put into their present position; the air expelled by the water through the valve e as before, and a new stroke prepared. It is scarcely needful to add, that if the vessel B contained ten times as much volume as the receiver A, the exhaustion of the latter at each emptying of the vessel B would follow this ratio—¹/₁₁, ¹/₁₂₁, ¹/₁₃₃₁, &c. thus approaching by rapid degrees to a perfect vacuum. The water, or liquid, used for this purpose would of course be as perfectly purged of air, as possible.

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OF
AN INCLINED WATER WHEEL.

The principal mechanical merit I conceive this Machine to possess, lies in the facility it gives of taking a stream of water as high, and discharging it as low as possible: and both nearly in the direction in which it naturally flows. Of the advantage it possesses in keeping the water a long time from falling, I shall not now speak, as it would require more discussion than this work comports; and, moreover, the Plate confines us to a somewhat contracted representation, which I hope my readers will excuse.

Plate 48 fig. 3, A B is the section of the wheel, and C D a small portion of it’s circumference—which shews the form and position of the floats a b c, &c. E is a floor on which the upper water flows, and from which it falls thinly on to the wheel—whose motion is purposely made as slow as possible. The water then, occupies one half of the wheel’s circumference, falls by a gentle slope and finally leaves the wheel at d, whether it there touches the lower water, or not. This wheel is allowed to be incapable of using to advantage a large stream of water—but is doubtless fit to employ a small stream, in the best manner.

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OF
A VESSEL,
To assist in taking Medicine, &c.

I have hesitated a moment to describe this method of helping the weak, in body or mind, to conquer their aversion to medicine—several persons having threatened me with a larger dose of ridicule than I am prepared to swallow. But surely, if we can only conquer a child’s timidity, so as to induce him to take, speedily, what his health requires, we shall not do a thing altogether laughable. We shall, perhaps, preserve a beloved child to the solicitude of a mother! and perhaps—a citizen to his country! If then, some laugh, more will approve; and I therefore continue the promised article.

Fig. 4 of Plate 48, shews this cup, composed of an inner and an outer vessel: the first to hold the medicine, and the latter a little tea, or other proper liquid to wash it down. The cups have a spout common to both; but the outer cup retains it’s contents as long as the small funnel a, is stopped with the thumb or finger. Thus then, the medicine is first taken, while the liquid is retained in the outer vessel—but the thumb being removed, the liquid also flows into the mouth, and in a good measure removes the taste it was wished to disguise.

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OF
AN AERO-HYDRAULIC MACHINE,
For raising Water in large quantities.

The art of constructing Mills, or Machines to be driven by the wind, is so well known, that the results are considered as being, very nearly, what a perfect theory would require. It is, therefore, no part of my purpose to discuss either the theory or practice of that art. But I think that a still wider grasp may be taken of this powerful agent, so as to secure a further degree of utility, even while following less closely the abstract principles of mechanical philosophy. I enter then, directly, on the description of another of my wind Machines, in order to give an idea of the means I contemplate for losing the importance of those details in the magnitude of the general effect.

This Machine (see Plate 49, fig. 1,) is capable of great results merely because it employs, at a small expence, a great mass of air in motion; whether ill or well, is not the question: for as this source of power is almost indefinite, methinks we may draw from it without reserve. The present method of so doing, consists in using a very large sail, (A B) both to receive the impulse of the wind, and to raise the water. This figure is a section of the Machine in it’s length:—and it’s width (not represented) is as great as the occasion may require. The sail is here shewn as placed over a lake or other sheet of water which it might be wished to drain, (or which may serve as a mill pond to drive any required Machines, by the water thus raised.) C D is the water in it’s lower bed: and E, is a canal on a higher level, into which a large quantity is thrown at each manoeuvre of the Machine, a is the bank of the upper canal, to which is affixed the edge of the canvass, of which a B A d, is a section; and which might be large to immensity. At 1 2 3, &c. is a row of stakes as long as the Machine; and they are capped transversely with round poles, on which the sail rests when in it’s lowest position. In this state, also, the part b of the sail, plunges into the water, which rises above it in the prismatic form, b r s; a row of valves or clacks, (b) permitting it to rise through them, but preventing it from again falling that way. Thus, at every change, this prism of water, is sure to be replenished; and if we suppose the triangle b r s to have an area of ten square feet, and the prism to be one hundred feet long, the water there contained will be a thousand cubic feet—capable, however, of being augmented or diminished at pleasure, by slackening or tightening the sail towards A. At d, is the weather-end of this sail, which is supported when at rest, on the surface of the water, by the posts and caps before mentioned. This end d, of the sail is connected with a row of posts C F, placed more or less closely, as the prevailing strength of the wind and the size of the sail may require. The sail is held to these posts by rolling pulley frames, of which one is seen at g, and is drawn up and down by the rope g h, acting at one end directly on the rolling pulley-frame g, and the other on the sail d, after having passed over a pulley (F) in the post itself: where note, that this effect can be communicated by proper machinery, from any one of these posts (C F) to all collateral ones; so as to make the manoeuvres general, across the sail, whatever be it’s magnitude.

The following then, is the operation. The wind blows (by supposition) in the direction of the arrows in the figure: and the rolling pulley-frame g is quickly drawn up to g, where the hook i holds it fast. By a necessary consequence the wind fills the sail d c r, and stretches it into the figure d A B a: in doing which it lifts the water r s, and pours it, in all the width of the sail, into the canal E; thus raising a thousand cubic feet of water at each stroke. As soon as the water is turned into the canal E, the hook i is pulled outward, and the rolling pulley g is forced down, by the wind itself, to the position k, when the wind blowing over the sail, will give it a bent form, (k c a) and soon bring the sail into it’s present position on the posts 1 2, &c.—when water will be again admitted by the valves at b, and another stroke of the Machine be prepared.

The above contains the basis of this idea. I do not expect it will obtain at once universal assent: But if I knew the several grounds of objection, I am persuaded the greatest number of them could be removed. The first I anticipate, is the difficulty of turning this Machine to the several winds that may blow over it. To this objection I would reply, that in such a case, the canal E, should surround an area made large enough for the sail, of some polygonal form, say an octagon, to different sides of which the stretching cords of the sail should be carried, so as to catch the prevailing winds—but the direction of which need not be followed to a nicety; since an obliquity of a few degrees would not prevent the effect.

It might be added, that it is not indispensable that the canal E should be stationary. Made of wood, or metal, it might turn round a fixed centre, and be braced into the necessary positions with ropes—when the posts only (C F) would have to be removed, or quitted for others duly placed. These ideas are connected with immense effects; and cannot, therefore, be lightly disposed of: they both deserve and require serious attention.

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OF
ANOTHER WIND MACHINE,
Furnishing immense Powers.

This is the last of those conceptions I shall now bring forward, for making more than a common use of the WIND as a first-mover of Machinery. Horizontal windmills are well known; and this is a horizontal windmill—yet not like those already in use: for, here, the sails, very large and numerous, are placed on a boat in the form of a ring, which thus moves through the water without any other resistance than that arising from the asperities of it’s surface.

In Plate 49, fig. 3, B B is a section of the Vessel, placed in a circular canal D, into which the lower water flows through proper arches (C C) in the banks. The vessel is rigged with several narrow horizontal sails, stretched on ropes between the oblique masts a b, c d; and so placed, that the sails (being a little wider than the interval between the ropes) can open in one direction, but not in the other; and they are shewn open at c d, and shut at a b, in the figure. This, therefore, is a mill, that takes all winds; and although it’s uses might be various, we shall finish it’s description as adapted to raise water by the centrifugal force. As before hinted, the canal D D is circular; and has a bank, sloping outward, with a canal (E) on it’s top. When, therefore, the wind blows, the ring boat B (held to the centre by the ropes f g) revolves around it; and by one or more water drags (h) which it carries, collects the water on and up the bank, and finally drives it into the canal E, from which it flows in any destined direction. If for draining watery lands, it will be done rapidly; if for irrigating, it will be done abundantly: if, in fine, for driving any mill with the water thus raised, the machinery will be very efficient, as working with ten or twenty times as much sail, as any other windmill can carry. I add, merely on this occasion, that the sails here mentioned, might be placed obliquely, instead of straight across the ring vessel; (see the plan in fig. 2 of this Plate at E F) from which disposition, nearly all the advantages of the vertical mill might be transferred to the horizontal; and with this remark I leave the present interesting subject to the studious and candid reader.

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OF
A CENTRIFUGAL MIRROR,
To collect Solar heat.

My fiftieth and last Plate contains this idea: It is not intended to vie with the usual mirror, in correctness of form, or intensity of local effect—but to offer, by the largeness of it’s dimensions, some properties which better mirrors cannot present. It is intended to pave the way for the use of the Sun’s rays in Engines of Power. For this purpose, however, it must probably be transported to some tropical climate, where “a cloudless sun” diffuses it’s rays more constantly, and less obliquely, than in our northern climes.

This is the more necessary here, because this Mirror can only be used in a horizontal position, and is in fact a fluid Mirror. Fig. 1, shews it mounted on a steady frame A B, and having a strong axis on which it can be turned, faster or slower, according to it’s dimensions; and it may or may not be floated on water, to lessen the stress on the axis. The Mirror, properly speaking, is composed of mercury—contained in the revolving vessel C D, whose motion should be given by proper machinery in the most uniform manner possible. The mercury, thus turned, acquires a concave surface, a, b, c; and receiving the parallel rays d c, e b, and, f a, collects them into the focus F; in, or near which, is placed the vessel where the effect is to become useful, and which of course is moveable so as to follow the sun’s motion. Those of my readers who have seen the machines used for fixing the sun’s image in the solar microscope, will be at no loss to conceive how our present focal station must be moved to adapt it to a fixed mirror. I shall only add further, that it is not necessarily an exact movement that is here wanted; since the vessel to be heated would have dimensions somewhat large, and the focus itself be only brought to a moderate degree of precision. In a word, the utmost heat wanted would be, what could be usefully employed in heating water. It remains then to be observed, that the source of power, in this Machine, is magnitude of parts, more than precision of form: yet it may be mentioned, that the form we thus procure in the revolving mercury, is a solid of revolution, having the logarithmic curve (a, b c) for it’s section—a curve, which in fact, comes indefinitely near to the parabolic figure which would be required, if greater precision were attempted. We finish then, by observing, that the bottom itself of the revolving vessel might be made concave, (like the dotted line under that a b c) in order to avoid the necessity of using a large quantity of mercury, to form the reflecting surface.

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OF
A SECOND MIRROR,
For collecting the Sun’s rays.

This Mirror seems superior to the former, as depending on fixed materials. It likewise, produces the desired effect, by offering a very large surface to the sun, and directing the rays to a focus, nearly enough to give the heat required for water, as before mentioned.

To do this, a frame A (Plate 50, fig. 2) holds the Mirror; and this frame has a horizontal motion round the post B, something like a common windmill. In this frame and on two horizontal trunnions, turns the Mirror C D: and one or both these trunnions are hollow, to admit of a process we shall shortly mention. This Mirror itself is composed of an air-tight ring C D, of a width proportionate to the diameter adopted; and on which are fixed two heads, much like those of a tambourine, (or the under head might be made of some metallic substance). The head a b c, is made of a fine texture, duly prepared and varnished till it becomes air tight, and then there are stuck to it, a number of small hexagonal looking-glasses or mirrors of any kind, (see fig. 7) which thus fill up the whole space, and prepare the Mirror for the intended change of form. The method of giving this form, consists in exhausting, more or less, this tambourine of air, when, by the pressure of the atmosphere, the heads will take the form a b c, that is a spherically concave form—fit to reflect the sun’s rays as correctly as this our object requires; and thus may some thousand small images of the sun be brought to fall on the same spot, and an immense heat be occasioned. The accounts we have of the destruction of the Roman fleet by the united mirrors of Archimedes, make this process appear the more feasible—as whatever were the methods of uniting the foci of his mirrors, a similar effect may be expected from this simple process.

My readers will perceive that this Machine has the advantages of the universal joint, by which it can be directed to the sun in every position; and even made to fix his ardours on any immoveable spot for a good length of time. The persons to whom I particularly address these ideas, will require no further details to conceive the less obvious circumstances of this Invention. In general, we want no effect that requires optical precision: but if we did, it could be obtained to a good degree, by methods similar to these.

I shall only add here, that this fig. 2 is given as a section—because intended to represent a parallelogram, as well as a solid of revolution: and thus (with proper mirrors) to make what now appears a spherical focus, a linear one—fit to heat a cylindrical vessel with it’s contents; and thereby draw power from the sun’s heat, without running expense. I am serious when I say, that we can thus, practically, collect the solar rays which fall on many hundred square feet of surface; and produce by them, at any desired distance, effects to which those obtained from modern burning mirrors, are but as sparks to a blaze.

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OF
AN ENGRAVING MACHINE,
For large Patterns.

This Machine supposes at once a new kind of engraving, and admits of patterns of very large dimensions. This kind of engraving will be best understood by persons acquainted with figure-weaving; and especially with the manner of mounting the looms for that purpose. In that System, (see Plate 50, fig. 8) the patterns are drawn on ruled paper divided into squares; and each of these squares represents a point in the texture, composed of one or more threads each way; insomuch that whenever that square has any desired colour in it on the pattern, it’s threads are taken by the person who prepares the loom; and they are missed in every case where nothing appears in that square, or a colour not then wanted. Now, whatever be the dimensions of these elementary points on the loom, they may be represented by squares of any convenient size on the pattern: only remembering that the smaller they are, in reality, the better will be the delineation. Thus in carpeting, for example, an element of this kind may be a square of one tenth of an inch and more; while one on a ribbon or a piece of silk, is often not the hundredth part. And therefore, the perfection of this engraving depends on the fineness of the points of which the figures are composed. For, in a word, this System proceeds on the same principle. When any part of a line requires a dot or mark to be made, the Machine strikes a blow there; and when no impression is to be made, the Machine (by means that will be shewn) suffers the cylinder to pass that place without striking. The means of regulating this is committed to workmen who merely know how to read off the pattern in it’s length, as it is now read off in it’s width by the weaver. To describe the construction of the Machine, (as exhibited in figs. 3 and 4 of Plate 50) A is the cylinder to be engraved; and B is a worm-wheel fixed to it’s mandril, and destined to turn it. This it does, slowly, by the endless screw a, as turned by proper straps on the fast and loose pullies b c, (figs. 3 and 4). C shews a second wheel, concentric with that B, but running loose on it’s axis, which is a pin fitted into the end of the mandril. This wheel, when the threads of the screw a are fine, requires a motion more rapid than the wheel B—to give which motion by means of the latter, we use a pair of multiplying wheels d, which geer, one in the larger bevil wheel cut near the edge of the wheel B; and the other in a smaller bevil wheel cut or fixed on the inner face of the wheel C—and whence this latter wheel receives a velocity of about ten times the speed of B. The use of this wheel C, is to carry, across the Machine, certain bars, of wood or metal, shewn in figs. 5 and 6, whose function is to carry short pins or studs 1, 2, 3, 4, &c. for the purpose of determining the places where the punch is to act, and where it is not. To this end, g h is a frame, which is raised by a cam or tappet i, fixed in the endless screw a, once every turn; and that through the medium of the little tumbler i e f, by which is finally determined whether the stroke shall take place or not—for m being a section of the stud bar of figs. 5 and 6, it’s pins, when they occur, raise the end f of the bent lever f e i; and when there is no pin or stud in m, this lever is not raised, and the point i, does not come near enough to the cam to be laid hold of, in which case no stroke is given. This then, is so whenever the studs fail in the bar m; and these fail whenever the pattern-reader has said to the stud-setter, miss: and they occur whenever he has said take—both which cases happen more or less often according to the state of the squares in the pattern.

To be a little more particular: in fig. 5 we see a part of the wheel C of fig. 3, and also a part of the stud bars m m, which geer in the wheel C, and which being conducted by the guides n, follow the motion of that wheel, presenting at f, (fig. 3) a stud to raise the lever f e, whenever the pattern requires it. It may be mentioned, that these studs act obliquely on the wing f of this lever, and thus raise it as they pass under it. And further, these stud bars are made and fitted to each other in the manner shewn at fig. 6. There is a geering tooth under every stud hole, and the last stud hole of a given bar has, fixed in it, a thin tube a, into which the stud enters the same way as in any other place: but this tube whether studded or not serves to lay hold of the succeeding bar b, by it’s first hole—so, in fine, as to make the bars endless; the attendant having nothing else to do than to hook them to each other as the wheel C draws them in.

Thus then, are the strokes of the hammer frame, g h, conformed to the pattern: for these bars have been studded before hand by one or more readers and setters; and it is a merely mechanical process to put them in while the Machine moves: from which, by the bye, they fall out after the passage into a proper box, and the studs out of them, to be composed again from the succeeding figures of the pattern. A dozen or two of these bars might be prepared at any time and place, and to any pattern, which they will thus transfer to a cylinder at any desired moment, without the further preparation of dies, punches, mills, &c.—as used in other Machines. N. B. The strength of the blows thus given by the hammer frame g h, is lessened or augmented by the position of the point i fixed to the bent lever i e f, and which makes that lift higher or lower as required—which is a mean of shading offered by this Machine. But to mention it’s other properties, the endless screw a, (figs. 3 and 4) carries another endless screw o, more or less fine, which turns at the same time the wheel p, and, by that, the long screw s s, whose office it is to shift, slowly, the punch carriers k l, along the Machine, from k by l, towards s. And here an observation occurs: this can only be so, when the pattern permits the action of the punches k or l, to take place spirally on the cylinder; that is, when the sketches are distinct enough not to shew the anomaly that would occur were a straight pattern thus transferred to a set of spiral lines. But should it be desirable to engrave patterns so correct as to require an exact parallel motion round the cylinder, then the motion of this screw must not be continual—but must intermit and be resumed, at every beginning of a new line round the cylinder. I hope, I make myself understood: a pattern drawn on squares, produces lines all parallel to the first; while the spiral motion of the punch causes a slight deviation—which, in a word, can either be suffered or avoided. At all events, this deviation is so much the smaller as the punch motion is slower in both directions; and, in fine patterns, must be very small. One remark will close this part of the subject: although a fine pattern, requires a great number of blows, and thus a certain expence of time, each blow can be so much the lighter and more frequent; so as to compensate, in some degree, for this cause of delay. I add, that the levers shewn above and around fig. 6, are intended to lift the hammer frame g h, equally at both ends: while the screw Z regulates the depth to which it is permitted to fall.

I observe, finally, that, according to the size of the intended pattern, there are more or fewer of the punch bearers k l, connected, by their nuts, with the screw s s; each of which thus engraves it’s sketch, similar to the collateral ones; and that were it wished to make one pattern of the whole length and circumference of the cylinder, a single punch bearer would be required—since nothing else limits the extent of a pattern engraved by this Machine.

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Thus have I gone through my proposed “Century of Inventions,” for every imperfection in which I beg the indulgence of my numerous readers. And here I can truly say I have neglected nothing—although the precarious state of my health may have sometimes veiled the evidence of my descriptions. On the other hand, I did not even attempt many of the lesser details of execution; as I wrote for those to whom they would have been superfluous: but as to the objects themselves, I believe there is not one that is without the pale of practical utility. In a word, many of the subjects have been frequently executed, and are in daily use: and as to those which remain to be tried, I engage, if called on, to give them useful existence. And the better to convince candid minds of the serious attention I have paid to these subjects, I shall add the scales on which they have been executed, or to which they are drawn—those scales expressed by a fraction, shewing what proportion the figures bear to the reality. Thus the scale of one inch to a foot will be expressed by the fraction ¹/₁₂; that of two inches to a foot, by ¹/₆, &c. that is, the figures, in these cases, will be (nearly) ¹/₁₂ or ¹/₆ of the size of the Machines. This premised—and also that we shall observe the alphabetical order, the following is the