WILLIAM CHAPMAN, of the town and county of New◄ castle-upon-Tyne, Civil Engineer; for his method or methods of conveying coals and other minerals in the working of mines or below ground, and of returning the empty vessels and carriages, so as to save much labour and expense. Dated April 27, 1808. Specifi cation to be enrolled within four months.

WILLIAM BELL, of Birmingham, in the county of Warwick, Engineer; for an improvement in making pipes or pumps for conducting water and other liquids. Dated April 30, 1808, Specification to be enrolled within one month.

EDWARD COLEMAN,: Professor of the Veterinary College, in the parish of Saint Pancras, in the county of Middlesex; for certain improvements in the construc→ tion and application of a horse-shoe, which will completely prevent several diseases to which the feet of horses are subject, more especially that very general disease called contraction of the hoof, and is also particularly adapted for flat convex feet, for horses of cavalry, and for hunting, and for all other purposes where the loss of a shoe, is productive of great inconvenience,

Dated April 30, 1808. Specification to be enrolled within one month...

Specification of the Patent granted to DANIEL DERING MATHEW, of Upper Mary-le-bone Street, in the Parish of St. Mary-le-bone, in the County of Middlesex, Esq.; for certain Improvements in the Construction of Watches and Chronometers. Dated April 27, 1808.

With a Plate.

To O all to whom these presents shall come, &c. NOW KNOW YE, that, in compliance with the said proviso, I the said Daniel Dering Mathew do hereby declare, that the nature of my said invention, and the manner in which the same is to be performed, are particularly described and ascertained as follows; that is to say: In the drawings hereunto annexed, Fig. 1, (Plate IV.) represents (in the manner of a plan) those parts of the structure of a chronometer which are more immediately, employed in maintaining the vibration of the balance, and are distinguished by the name of the 'scapement or escapement. The letters a A, b B, c C, d D, e E, f F, indiVOL. XIII.-SECOND SERIES.

L

cate

cate the teeth of two wheels, equal and similar in all respects, which are fixed upon the last arbor of the train; and the dark-shaded teeth marked by small letters belong to one of the said wheels; and the light-shaded or outline teeth marked by capital letters belong to the other of the said wheels, and are so placed, that, in the order of rotation, the points or extremities of the teeth of one wheel do respectively stand in or near the middle of the interval between the points or extremities of the teeth of the other wheel; and the number and figure of the teeth to be made in the said equal and similar wheels may be such as the constructor shall think proper, according to the number of beats he may be desirous of producing in any given portion of time, and the nature of the material out of which he may think fit to make the wheels; or otherwise a single wheel may be used instead of two, and the teeth be made to stand contrate in the form of pins, or of any other suitable form, as in Fig. 2; or otherwise (but not by preference) a single wheel may be used. G and H are the working extremities of two pallets, of which the levers or arms terminate in distinct or separate axes or centres of motion; but the said axes are nevertheless so disposed, as to cause the motion of the said arms to be concentric with each other, and with the balance itself; or, in other words, the pallets and the balance do each move in different planes upon one and the same imaginary line or virtual axis. NN is the potence, or piece by which the pallets and the balance are supported. K and L represent back-springs, -which urge the pallets towards the wheels (the said pallets being so placed in the potence, that one pallet shall apply itself to one wheel, and the other pallet to the other wheel respectively; or to the opposite sides and

faces

faces of a single wheel, if adopted in preference to two wheels as herein-before described); and to each lever there is opposed a stop, which prevents the pallet thereunto belonging from advancing so far as to touch the rim of its correspondent wheel. And the said backsprings may be respectively adjusted, with regard to their strength and action upon the said levers, by means of a screw applied to each, or by setting or bending, or by taking down the thickness thereof, as is well known to. artists, and may by their action upon the balance altogether supply the place and office of the spring usually called the pendulum spring. And for the better obtaining and effecting this and other desirable purposes, a compensation for heat and cold may be applied in any of the usual methods unto the said springs, in case the same shall be preferred to a compensation on the balance itself; and the strength and action of the said springsmay be regulated, and rendered more equable, in the several angular positions of the levers, by the interposition or use of a part or piece equivalent to the tumbler in a gun-lock, or to the jointed connection between the main-spring and a lever from the axis of the cock, as is sometimes done in the same instrument; both which, as is well known, do alter the action of the said mainspring, and might by a due proportion of the parts be applied (if needful) to equalize the same; and I do so proportion and apply the said contrivances in some of my said improvements.

And I do make the face of each of my pallets to consist of an inclined plane, as seen in Fig. 1, or more distinctly at rt in Fig. 5, ending at t in a claw or detent, against which, in the detent H, Fig. 1, the tooth dis seen to rest, and prevent the wheel from running down;

and the said inclined planes are made to proceed im wards from the levers towards the wheels or wheel, in the same direction as the said wheels or wheel when at 'liberty do move. And in order to insure the locking of the tooth upon the claw or detent, so as to prevent the possibility of any trip or disengagement of the wheel at an improper time, I do, when thought needful, make use of a banking-pin fixed to the arm of the inclined pallet, as seen in Fig. 6 at g, which keeps the pallet from going farther back than is necessary to allow the tooth to raise up the pallet to its detent by means of the catch p, the end or joint of which is a very slender spring. And I do make or form a circular part standing out from the lever of the said catch, against which part the crank of the balance first acts, so as to remove the said catch out of the way of the banking-pin, until it has knocked out the detent, and set the wheel at liberty.

And lastly, I do make the verge or axis of my balance in the form of a crank, as in Fig. 4, in order that the vibration upon its pivots, concentric with the axes of the levers of the pallets, may be performed without any other interruption or action than is intended to be produced by the pallets themselves; and I do so place my balance, that the arm or extreme branch of the said crank shall lie or be disposed between the levers of the said pallets 'as at M. And the action of the said escapement, as delineated in Fig. 1, is as follows: the wheels being urged by the maintaining power to move in the - direction marked by the small arrow at V, are prevented from revolving by the detent of one of the pallets (for example H), which holds against one of the teeth (for example d); but, as soon as the balance is by external motion made to vibrate, and its crank M comes to drive

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