Has a solid piston (so called,) which has a hole in its back end to allow the feed-screw to pass in without touching; the drill is secured to this piston. On the back end of the piston is a section of a ball used as a cam, which works the valve and the feed-motion. The valve is rotated by a rod lying on the band of the cylinder; upon this rod are two cams which perforate the band of the cylinder. The action of the piston brings the ball on its end in contact with these cams, rocking them up and down; the rod to which they are secured being connected with the valve, imparts to that its motion. This machine is fed altogether on ways, or a bed-piece, upon which is the feed-screw; the feed-nut is upon the end of the cylinder-band. To this feed-nut is attached a feed-ratchet, which is held between two collars, allowing it to turn round. Upon the cylinder-band is a lever, one end of which passes through the band; upon the other end is a pall. The motion of the piston raises the lever up, pressing the end containing the pall against the ratchet which turns the nut on the feed-screw, thus moving the machine forward. The rotating ratchet is in the band of the cylinder and has a spline in it, and a pall on its outside. The piston having a spiral groove is turned by this ratchet as it moves down. On the return of the piston, the pall drops into the ratchet and then the piston is turned. The piston is not encumbered with any machinery, and moves alone; its area of air is greater on the forward than on the backward stroke; the alternation of the valve admits the air. The machine, like the one last described, contains eighty pieces; it has the same number of screws and pins, and weighs 372 pounds including the ways or bed-piece; without the ways its weight is 212 pounds. Its number of strokes is about 300 per minute, and its blow somewhat lighter than that of the other. This machine is not entirely automatic; the feed-motion not working regular; when it does not, it is fed by hand, which is a simple process. These machines stand the work much better than those first made at Fitchburg. Their average time in the tunnel without repairs in the interval, is about five days; they have needed repairs in two days; one remained at work fourteen days. They accomplish double the work without repairs that those do which were made after the previous pattern. There is a further advantage in using the Burleigh machines; their breaking, when it occurs, is not very serious, the injured parts consisting mainly of cams, can generally be replaced at the tunnel; whereas for the repairs on the Brooks, Burleigh and Gates machine, the dependence to a very great extent has been upon the machine shop at Fitchburg. The piston-head of this machine has a diameter of 4-25/100 inches. The diameter of the piston-rod is at the large end, 3 inches, at the small end, 2-75/100 inches.