430 
STEPHENSON’S PATENT 
Fig. 15. 
Fig. 16. 
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 
c}dinder ; 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, (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.