430 



STEPHENSON'S PATENT 



FIG. 1C. 



the outside ; the joints and the space between the flanch and the plate are run with 

 lead all round to make the cylinder quite firm and steady, as the hole in the plate 

 does not accurately fit the cylinder ; the joint at the other end of the cylinder is also 

 run flush with lead for the same reason. The flanch is fixed to the plate by six three- 

 quarter inch bolts, which are screwed into the flanch from the outside, in order that 

 they may fit closely to the holes in the flanch and the plate, and hold the cylinder quite 

 steady. A flanch SS is cast on the inside of the end of the cylinder, projecting 

 into the cylinder, and the cover T is bolted to the outside of this flanch, 

 having a projection in the centre that fills up the opening, and makes the end of 

 the cylinder even or flush inside ; the cover is fixed on by six bolts, screwed into 

 the flanch of the cylinder, and having nuts on them on the outside ; the bolts are 

 made square where they pass through the cover, to prevent their turning when the 

 nuts are screwed on. It is not required to have ready access to this end of the 

 'cylinder ; but at the other end it is necessary that there should be no obstruction, as 

 the cylinder is required to be completely opened occasionally to get the piston in and 

 out. X (Plate XC.) is one of the pistons ; there is one in each cylinder, fitting the cy- 

 linders accurately, so as not to let any steam escape between them and the cylin- 

 ders when they are moved backwards and forwards. The piston is made entirely of 

 brass, and consists of a plate, A, (figs. 15 and 16,) five-eighths of an inch thick, 

 having a boss, B, cast on the centre, with three arms, CCC, three quarters of an inch 

 thick, also cast upon it, radiating from the centre and equidistant from each other. 



