88 Tmprovement of the Drill Plough.[Feb

center of the first of these holes must be five inches distant

from the closed end A; the center of the second hole must be eight inches distant from the center of the fixst; and s0 on till six holes are made longitudinally along the cylinder. Then another such line of six s1umilar holes 1s To be made on the opposite sìde of the cylinder, and then two other such lines between the former, in all twenty-four; and the size of all these holes must be nicely observed, as well as their distances.---Secondly, the wooden cylinder fixed on the axis 1s Now to be introduced into the tin cylinder, but not

uite to the end of it, but s0 as to leave exactly one inch of void space at the closed end A, and then the size of all these apertures through the tin cylinder, cach of which is exactly half an inch wide and five eighths of an inch long are to be mecely marked with a fine point on the wooden cylinder, which must not previously have any excavations

made in it.—Thirdly, the twenty-four holes, thus marked*

on the woodcn cylinder, are now to be excavated exactly three eighths of an inch deep, but with an addition also of three cighths of an inch at that end of every one of them which 1s next to À, s0 that when the wooden cylinder 1s again replaced in the tin cylinder as before, with one inch ot void space at the closed extremity of it’; the excavations in the wooden cylinder will be three cighths of an inch longer than the perforations in the tin cylinder over them. These excavatious in the wooden cylinder must, also, be rather narrower at the bottom than at the top, to prevent, with certainty, any of the grain from stickmg in them as they revolve.—Fourthly, a screw of iron about three inches long, with a square head to receive a screw-driver, is to pass through the end A of the tin cylinder on one side of the ax15.5. 98 at, x. Fig. 4( The screw.: part af. this 1s,te, lle, in a hollow groove of the wooden cylinder, and to be receiv- edin a nut or female screw, wluch 1s fixed to the wooden cylinder—The head part of the screw, which passes through the end À of‘the tin cylinder at, x. must have a shoulder within the tin cylinder, that it may not come forwards through the end of it; and a brass ring must be put over the square end ot the screw on the outside of. the tni cy- linder, with a pin through that square cud of the Screw to hold on the brass ring. Thus when the square head of the screw 1s turned by a screw-driver, it gradually moves the tin cylinder backwards and forwards, one inch on the wooden one, so as either to press the end À of the tin cy- linder into contact with the end of the wooden cylinder within it, or to remove 1t one inch from it, and leaye a void space at the end A.—Fifthly, the ends of all the holes of the tin cylinder, which are next to the end À, are now to be