Award of Medals, ^c, at Kilburn. 
729 
depressed, to any pressure required, by means of a tightening screw, in an angle 
plate, so that it can be adjusted to the nicest requirement. From the above it 
^•ill be seen that when undue pressure is applied, either to the feeding-board or 
the hood, the drum-mouth is at once closed hy the meeting of the feed-board 
and the flap-lx)ard, and both are securely locked, and cannot be opened until 
the locking spring is released by the hand out of the ratchet teeth, when the 
feed-board by its weight falls open. The flap-board still remains closed until 
the locking rack is released by the hand chain. The board then falls back, 
leaving the drum-mouth open for work. It would be very diflBcult for any 
one to get into the drum of the machine. The mechanism is simple, efficient, 
and not Uable to get out of order. It will be seen that the hood is made in 
two parts. The upper portion can be turned back when its position is found 
to interfere with the feeding of coarse materials into the drum. 
Francis Ley, of the Vulcan Malleable Cast-iron Works, Derby, 
received first-class mention for introducing the manufacture of, 
and improvements on, Ewart's Patent Detachable Driving-Chain. 
Hitherto this valuable means of transmitting power has been 
made only in America. Mr. Ley is able to supply it on the 
same terms, the purchaser saving expenses of carriage. Nor is this 
all. Important improvements have been introduced, which render 
the article much more accurate. First of all, as regards the metal : 
much attention has been paid to the production of malleable 
castings that are strong, durable, and homogeneous. The metal 
has the appearance of a mild steel ; it is very ductile, and may 
be readily stamped, punched, drawn, or twisted, without heating. 
When turned it takes a high polish, and when burnished is 
peculiarly rich. It can be readily hardened, not being blistered, 
scaled, or warped, in the process. It is therefore specially suit- 
able for chain gear, where the friction on the links is so con- 
siderable. Mr. Ley has introduced special machinery for the 
mouldings of the links, in which accuracy of pattern is of the 
greatest importance, not only as ensuring a secure joint, but also 
enabling^ the links to be removed. Instead of moulding from 
loose patterns, as on the American and English system, he has 
invented a system of moulding the links from stereotypes, which 
produce marvellously accurate castings. The stereotypes insure 
perfect accuracy in the pitck of the chain, as no rapping or other 
carelessness in moulding can render the casting imperfect in 
dimensions. Thus the chain must always work true on the 
wheels. The shape of the links has been altered from the 
American pattern. The latter are straight at the neck, whereas 
in these they are bulged out slightly, thus preserving the sec- 
tional area throughout. This is considered a great improvement. 
Mr. Ley is prepared to guarantee the metal to stand a tensile 
breaking strain of 25 to 28 tons per square inch with a fair 
amount of elongation. The nature of the chain will be readily 
understood by the subjoined drawing (Fig. 26, p. 730), which 
represents four links, the upper one partly detached. 
