be proved, by every part of the fourth cavity of the calf's stomach having the property of coagulating milk, This property in the general' secretion of the stomach leads Weak sto machs can digest only solid to an opinion, that the coagulation of fluid substances is necessary for their being acted on by the solvent liquor; and a food. practical observation of the late Mr. Hunter, that weak stomachs can digest only solid food, is in confirmation of it. That in converting animal and vegetable substances into chyle, the food is first intimately mixed with the general secretion of the stomach, and after it has been acted on by them, the solvent liquor is poured upon it, by which the nutritious part is dissolved. This solution is afterward conveyed into the pyloric portion, where it is mixed with the secretions peculiar to that cavity, and converted into chyle. The great strength of the muscles of the pyloric portion of some stomachs will, by their action, compress the con tents, and separate the chyle from the indigestible part of the food. In animals whose food is easy of digestion, the stomach consists of a cardiac and pyloric portion only; but in those whose food is difficult of digestion, other parts are superadded, in which it undergoes a preparation before it is submitted to that process. III. Description of a Machine for Printing Paper Hangings. By Y By this machine the printer works with greater facility and Advantages of dispatch than in the usual way; and the tereboy, who could this machine. with great difficulty serve one sieve, can by its means serve two with ease to himself. For this improvement the honorary silver medal was voted to Mr. Middleton by the Society of Arts. The following description shows the nature of this apparatus for facilitating the operations in paper-staining, and the mode of using it both for light and dark grounds. * From the Transactions of the Society of Arts, for 1807, p. 135. Method Description of Method of printing Light Grounds. Pl. I, fig. 1. A, the printer's table covered with a soft blanthe apparatus. ket. B, the woollen cloth sieve on which the colour is laid and spread by a boy (called the tere-boy) with a hair brush, This cloth sieve is laid upon a leather sieve impervious to wet, and it floats upon some gum liquor, in a wooden vessel C. Method of printing light grounds. D, D, two cords of 36 feet long, stretched from the table A to the other end of the room, and kept tight by a weight at B. F, F, an endless cord, passing round a grooved wheel G under the table, over a pulley H, in the side of the table, and and over another I, at the other end of the room. Its use is to carry the cross-piece K, called the traverse, which is fastened to it. L, is a wheel fixed on the same axis as the wheel G, but on the outside of the boarding of the table; it has three pegs projecting about four inches from its face. This wheel is moved by the printer setting his foot on one of the pegs. Fig. 2, is the traverse on a larger scale. M, M, are two pieces of wood connected by a hinge at N, and when closed are retained in that position by a ring O, put over the ends of them it is connected with the endless cord, by a staple P on one side, and another staple on the other side, and slides along the cords D, D, by means of two pullies R, R. The operation of printing commences by putting one end of the paper to be printed (which is 12 yards long and 23 inches wide) between the divisions of the traverse (fig. 2), and fastening it there by the ring O. The other part of the paper, except what lies on the printing table, is wound round the roller S. The workman takes up the printing block with his right hand, dips the face of it on the woollen cloth in the sieve, which the tere boy had previously spread with colour, and then places the block upon the paper to be printed, giving it two or three smart strokes with a leaden mall held in his left hand; he then removes the block to supply it with more colour from the sieve; and during this operation sets his foot upon the peg in the wheel; and as he recovers his upright position to bring the block over the table, his foot presses the peg peg down into the position 2, which, by means of the wheel G, endless cord F, and traverse K, draws the paper forward on the table just the proper distance to print again. When the whole piece is printed, the tere-boy goes to the end of the room, loosens the paper from the traverse, and hangs it up to dry in folds, on loose sticks placed across racks attached to the ceiling. Method of printing Dark Grounds. The table and sieve for the colour are the same as in print- Method of printing dark ing light grounds. The difference of printing consists in ap- grounds. plying the colour from the block upon the table, by means of a lever, instead of striking the block with a mall; the pressure of the lever forcing a greater quantity of colour upon the paper and in a more even manner. T, the axle of the lever. Y, the arm (15 inches long) to which the power is applied by means of a rope U, fastened to it, which has a treadle W at its end, for the workman to place his foot upon. X, another arm (6 inches long) to which is jointed Y, a long pole, the end of which is applied to the back of the block 3, when the pressure is given, Z, au arm on the other side of the axle T, to which a weight is bung to balance the pole Y. Fig. 3, shows a section of the axle T with the arms V and Z projecting from it, and the manner in which the arm X is con nected by a joint with the pole Y; the excellence of this principle depends upon the very great increase of power, which is given by bringing the pole near the centre of the joint or axis. The paper being placed upon the table as in printing light grounds, and the workman having placed his block, furnished with colour, upon the paper to be printed, he puts his foot on the treadle W, attached to the cord U, takes the pole from behind the piece of wood 4, and applies its end upon the block U, and pressing down his foot makes the impression from the block upon the paper. He then lodges the pole behind the piece of wood 4, to be out of the way; he next removes the block to furnish it again with colour, and draws the paper forward for another impression, by the foot-wheel L, as described in the former mode. IV. IV. Chlorite shist cemented by crystallized tin. The mine described. Flookan di different An Account of the Relistian Tin Mine. By Mr. JOSEPH DEAR SIR, WHEN I mentioned the occurrence of pebbles of chlorite shist, cemented by crystallized tin, in the Relistian mine, you expressed a wish to receive a particular account of this noyel circumstance. The Relistian mine is nearly on a level with the surrounding country. The lode has been seen at the depth of 12, 25, 50, 65, 75, 81, and 90 fathoms from the surface. It is of different width in different parts; the extreme width is 36 feet, and in this part it is principally worked. As it extends east and west (which is its due course), its width gradually diminishes, till at the distance of 100 fathoms east it is but 5 feet wide. It is composed (excepting the metallic substances) of shist, chlorite, and quartz. In some parts the shist predominates, and in others the chlorite; the quartz is throughout the smallest component part. The engine shaft (sec plan A, Pl. I, fig. 4) is situate 8 fathoms north of the widest part of the lode (B). In sinking the shaft a flookan (C), about 2 inches wide, was discovered, bearing a south-east course, which cut the lode at an angle of 45°; and heaved and disordered it. At the depth of 12, 25, and 50 fathoms, nothing was discovered in the lode but the cavities from which the ore had been taken away during the former period working the mine. At 65 fathoms in depth were found, close to the flookan, a great number of angular fragments of shist, cemented by the same substance. At the depth of 75 fathoms the flookan (C) became 4 inches vided into four wide in the shaft (A), and continued of that size for 10 fathoms; it then became divided into 4 parts or branches (D), with a body of each diverging from its former course, and in this state it conpebbles be branches, tween them, tinued through the lode (B), of which the first 3 feet were |