one and seven-eighths inches; at eye through which screw passes two and three-fourths inches; depth, three inches; to have a square thread, three-eighths of an inch pitch, cut to receive screw one and three-fourths inches diameter. In the side of this bar is placed a set screw, with small hand-wheel to secure the throttle from closing or opening at will. Valve stem has a spiral end fitting into the recess described in relief valves, and is one and one-eighth inches diameter from end for a distance of about thirteen and three-fourths inches; it is then shouldered down to three-fourths inch diameter for the remainder of its length, eight and one-fourth inches, screwed at its end for a nut and washer. Over this, extending the whole distance, seven and one-fourth inches, between shoulder and under side of washer, is a tube one and three-fourth inches diameter, with a square thread, three-eighths inch pitch, cut on the external surface and working into the corresponding thread cut in eye of the crossbar. On to this tube is keyed the handle, having the eye countersunk for the nut and washer on the valve-stem to sink into it about three-eighths of an inch; handle of finished wrought-iron, seven and one-half inches long, one-half of an inch thick; one and five-eighths inches broad at eye, one and three-eighths inches at the end; depth of eye, one and three-fourths inches; diameter, two and one-half inches. Sleeve for exhaust pipe, finished cast- iron, flanges to suit the one on the three inches; thickness one- half of an inch; bolted to exhaust pipe by six finished 3/4-inch bolts and nuts.

Bed plates to be nineteen feet long, bottom plate nine inches wide by two inches thick; seven inches from center of cylinder to under side; blocks are cast on to carry the lugs on the cylinder, tops of which are planed, and a hollow block is cast for the center lug of cylinder, having jaws at each end strong enough to admit of keys being firmly driven in at the side to hold the cylinder from moving between them; where the slides come a rib two and one-half inches deep and one and three-fourths inches thick runs, giving the bed so far a T form; where the slides are placed for a distance of seven feet, the form is that of a rib with a flange nine inches wide by one inch thick at the top and bottom, the top flanges to be planed for the slides to sit upon; the slides to be six feet nine inches long, three inches face, two inches thick, set down to one and one-fourth inches thick for seven inches wide, where it bolts on the bed; bolts and nuts, seven in number, seven-eighths inch diameter. For holding down the beds twenty-eighth bolts with nuts one and one-half inches diameter and of an average length of eight feet are required, and for the frame work fifteen, one and one-fourth inches diameter, bolts and nuts of an average length of five feet; connecting rods to be eighteen feet from center to center, to be made with iron straps fitted in white pine, twenty-two inches deep in the center, six and one-half inches at ends, by ten inches wide; jaws, where brasses fit in for wrists, are fifteen and one-half inches long inside, with thickness of iron between brasses and end of wood two and five-eighths inches, through each of which passes two turned bolts one and one-eighth inches diameter with head and nut section of each side three and three-fourth inches by two and three-fourth inches; straps are three and five-eights inches wide, two and five-eighths inches thick, at ends tapering to three-fourths inch thick in center; passing through these straps and wood are sixteen bolts and nuts seven-eighths inch diameter. Brasses to be seven-eighths inch thick at ends, three- eighths at sides, to be bored