LIST OF PLATES.

Improvements in Agricultural Implements, &c.-Sheppard's Patent for Certain Improvements in Machinery or Apparatus for Planing, Sawing, and Cutting Wood, &c. PLATE XII. Clarke's Patent for Improvements in Night Lights, and in Apparatus used therewith.-Petit's Patent for Improvements in Fastenings for Stoves.-Liddell's Patent for Improvements in Apparatus for Preventing Explosions in Steam-boilers.-Johnston's Patent for Improvements in Steam-boilers.-Aitken's Patent for Improvements in Atmospheric Railways.

PLATE XIII. Thorneycroft's Patent for a Machine for Rolling, Squeezing, or Compressing Puddled Balls of Iron, and also for Crushing or Grinding other Substances.Stevelly's Patent for Improvements in Steam-engines.Kibble's Patent for Improvements in Transmitting Power in Working Machinery where Endless Belts, Chains, or Straps are or may be used.-Barlow's Patent for Improvements in the Construction of Keys, Wedges, or Fastenings for Engineering Purposes. PLATE XIV. Bailey's Patent for Improvements in Machinery for Manufacturing Looped Fabrics. - Sargant's Patent for Improvements in the Manufacture of Barrels for Fire-arms. PLATE XV. Atkinson's Patent for Improvements in the Construction of Wheels for Carriages.-Lowcock's Patent for Improvements in Ploughs.-Newton's Patent for Improvements in the Preparation of Caoutchouc, &c.-Woodcroft's Patent for Improvements in Propelling Vessels. PLATE XVI. Butterworth's Patent for Certain Apparatus applicable to Preparation Machines used in the Spinning of Cotton, &c.-Brockedon's Patent for Improvements in the Manufacture of Pills and Medicated Lozenges, and in Preparing or Treating Black Lead.-Harrison's Patent for Certain Improvements in the Manufacture of Cast-iron Pipes, and other Iron Castings.-Sangster's Patent for Improvements in Umbrellas and Parasols.-Geeve's Patent for Improvements in Preparing Wood for Lighting or Kindling Fires.

PLATE XVII. Poole's Patent for Improvements in Steamengines, Steam-boilers, and Furnaces, or Fire-places.Dixon's Patent for Improvements in Heating Air for Blast Furnaces, and for other uses.-Brown's Patent for Improvements in Stoves.

PLATE XVIII. Nickels and Nickels' Patent for Elastic Fabrics, and rendering Fabrics less Elastic.-Lister and Ambler's Patent for Applying Fringes to Shawls, &c.Cooper's Patent for Purifying and Clarifying Sugar, and other Articles.

PLATE XIX. Cookson's Patent for Apparatus for Burning Sulphur, and in the Manufacture of Sulphuric Acid.Lenox and Jones's Patent for the Manufacture of Sheaves and Shells for Blocks, &c., for Shipwrights, &c.-Bates' Patent for Getting-up Hosiery Goods, &c.-Charlieu's Patent for Rails for Railways, and Wheels for Locomotive Carriages.-Losh's Patent for Metal Chains for Mining and other Purposes.

THE

REPERTORY

PATENT

OF

INVENTIONS.

No. 1. VOL. IV. ENLARGED SERIES.-JULY, 1844.

Specification of the Patent granted to JOHN RICHARD LUND, of Cornhill, in the City of London, Chronometer Maker, for Improvements in the Construction of Compensation Balances of Chronometers.-Sealed November 25, 1843.

WITH AN ENGRAVING.

To all to whom these presents shall come, &c., &c.The object of my said invention is to remove a defect in the construction of the compensation balance generally used in chronometers (see fig. 10), which is a magnified drawing of such a balance, from which it is found, that when such a balance is adjusted to mean time for the mean temperatures, about 55° Fahrenheit, it will fail to correct the effects produced by changes of temperature upon the balance spring, at, towards, or beyond the extreme temperatures, about 30° or 80° Fahrenheit. From the nature of my invention, no alteration is required in the form of the compensation balance now generally used, as a pair of either of the compensation weights I am now about to describe are to be applied instead of the compensation weights in ordinary use.

To facilitate this description, I shall designate the one No. 1.-VOL. IV.

B

as compensation weight, Y, and the other as compensation weight, z. The compensation weight, y, is shown. in the annexed drawings at fig. 1, which, together with figures 2, 3, 4, 5, 6, and 7, are magnified drawings thereof and of its several parts. The compensation weight, Z, and its several parts or portions, are shown at figures 8, 9, 10, 11, and 12.

Description of the Drawings.

In fig. 1, a, is a portion of an arc of an ordinary compensation balance blade, and the remainder of the figure one of my compensation weights.

Fig. 2, is the underside; and

Fig. 3, a section of fig. 1.

Figures 4, 5, 6, and 7, represent the parts of this weight taken to pieces. b, may be called the platform, attached to the balance blade by the screw, b', as in the ordinary compensation weights, and as shown at figures 2, and 3. c, is a ring, to be sprung on the edge of the platform, b, having an upright piece of metal, c', rising from it, to which is screwed a similar piece of metal, c2. These two pieces, c', c2, may, together, be called the holder, and it is so constructed as to carry a circular lamina of brass and steel, or other suitable metals, d, and to be moveable round the platform, b. One end of the lamina may be passed through this holder, either to the right or left, and then secured by the screws, c3, c3, c3. At the other end of this circular lamina, d, is fastened, by the screw, d', a piece of hardened steel, e, or a piece of steel holding a ruby, the steel or ruby having a hole in it, the edges of which hole are carefully rounded off on either side. f, is what I call the "correcting weight," shown separately at fig. 7; g, is a screw, screwed into the platform, b, having its end formed into a pivot, as seen in fig. 7, upon which the correcting weight, f, is made to turn easily, but steadily and firmly. The end, f1, of the correcting weight furthest from the screw or pivot, g, is made of gold or other suitable metal, and attached to the remainder of the correcting weight by a screw, as shown. A pin is inserted at the point, h, and a spring, i, fixed on the platform, b, bears against this pin with sufficient force to prevent any oscillation of the correcting weight, f, during the vibration of the balance. To divide the resistance hereby occasioned to the action of the lamina, this spring

is placed on the right hand side of the correcting weight in the one compensation weight, and on the left hand side in the other. In the compensation weight, z, shown in the annexed drawings, figures 8, and 9, the platform, b, the ring, c, to be sprung thereon, and the holders of the lamina are similar to those used in the compensation weight, Y, already described. The parts of the compensation weight, z, which differ from those of the compensation weight, Y, are fully shown in figures 9, 10, 11, and 12. At the end of the circular lamina, d, furthest from the holder, there is a ruby, j, fixed, which, when the lamina is influenced by change of temperature, moves between the two screws, k', k, in the piece of brass or lever, k, of which fig. 10, is a face and edge view. k2, k2, are two screws at the other end of the piece of brass or lever, k, inserted in the direction shown in fig. 10. This lever, k, turns upon a pivot, l. m, is the correcting weight, and it is made to slide towards and from the centre of the balance on the pin, n, which is screwed into an upright piece of brass, c1, attached to the platform, b; o, o, are screws, the ends of which are used to regulate the freedom between the correcting weight and the platform; 1, 1, are pieces of ruby, of the form shown in fig. 12, which are fixed in the adjusting arms, P, P, by a brass wedge, 2, as shown in fig. 12, where 1, and 2, are respectively the ruby and the wedge.

Fig. 11, is a sectional and face view of the correcting weight; and

Fig. 12, are similar views of one of the adjusting arms. The parts marked, q, q, of the adjusting arms move stiffly in the correcting weight, and the ends of the parts, q, q, are burnished over in the countersinks on the under side of it. r, is a spring fixed upon the platform, b, by the screw, r, so as to keep the rubies, I, 1, in contact with the end of the screws, k, k2. My compensation weights are to be treated precisely as those in ordinary use to obtain the adjustment of the balance for the mean temperatures about 55° Fahrenheit, care being taken during this adjustment, and when the compensation weight, Y, is to be used, to place, by turning the lamina round upon the platform, a diameter of the circular hole in the correcting weight, marked, s, figures 1, and 7, coincident with, or immediately over, a line, t, marked on the platform, b, which, if produced, would pass through the

centre of the balance; and when the compensation weight, z, is to be used, like care must be taken to place a diameter of the circular hole in the lever, k, marked, s, immediately over a similar line marked on its correcting weight, m, by turning one of the screws, k, k2, inwards or outwards. At the same time, the screws k', k', should be turned outwards far enough to withdraw their points from the space at the end of the lever, k, between the points, x, 2, and the ruby at the extremity of the lamina placed in the middle of this space by turning the lamina. round upon the platform. The sides of the adjusting arms marked, 3, 3, fig. 8, should then be placed in lines at right angles with the line, t, drawn on the correcting weight, m, and the surfaces of the rubies, 1, 1, which form the inclined planes at angles of about 75° with the sides, 3, 3. Now it will be evident to those who are acquainted with the action of an ordinary compensation balance, that a change of temperature will alter the position of the correcting weights in both the compensation weights, Y, and z, by acting on their respective laminæ. As one end of the lamina in the compensation weight, y, is attached to a correcting weight by the screw, u, and in the compensation weight, z, the lamina is made to act on the shortest end of the lever, k, and so change the position of the correcting weight by sliding the points of the screws, k2, k2, up and down the inclined planes made on the rubies, 1, 1. Therefore, in the compensation weight, y, the end of the correcting weight, f', made of gold, will be carried, as the temperature approaches 30° and 80° Fahrenheit, nearer to the centre of the balance, and will become more and more effective at each variation of the temperature towards these extremes, thereby counteracting the gradual accumulation of error in the rate of the chronometer towards the extreme temperatures and for this reason, that the end of this correcting weight describes the arc of a circle, whose centre, g, is distant from the centre of the balance by nearly the whole radius of the balance. For the same reason the longest end of the lever, k, of the compensation weight, z, is similarly effective. The effectiveness of the correcting weights in the compensation weights, Y, and z, respectively, is also very much increased by the great difference in the distance of the ends of the correcting weight from the pivot, g, in the one, and by the