NOTES
�609
�paired with the crank a = (7-1- ... /. ... 0+, which (as before) finds its
bearing 1 in the link d. In this way we obtain a chamber-train in which the
piston c merely oscillates about its axis. Without discussing at all the use-
fulness of this form of engine, I may mention that something similar to it
has already been made in Morton's disc-engine (Deutsche Gewerbezeitung, 1857,
��Fio. 450.
p. 31). Morton has, however, impressed by the form of the older disc- engines, made his piston c and chamber d unnecessarily as portions of spheres, and prides himself on the fact that the piston of his machine does not make the wobbling motions of those of the older engines, and that it has not the slot, nor the chamber the diaphragm and packing pieces formerly required. He has thought it necessary, however, to make the sides of his chamber with plane inner surfaces, parallel to the axis of 4, the piston lying upon these in its two extreme positions.
63 (P. 413.) In the year before, 1858, a patent was taken out (dated 14th April, and taken out through Newton's Agency), for a steam-engine having such shoe-sole-shaped wheel pistons. Special packing-pieces were fitted into the ends of the teeth (Propagation Industrielle, iv., 1869, p. 179).
54 (P. 437.) [This statement, I am sorry to say, does not apply to this country, where, so far as I know, the constructive elements as such have never yet received any systematic treatment. I have had to make a few small alterations in Chapter XI. on this account, omitting a few sentences which applied solely to the existing continental treatment of certain details. Professor Reuleaux's discussion as to the subdivision and classification of the constructive elements has therefore no direct bearing, as yet, upon English text-books, and hardly any upon English systems of instruction. I hope sincerely that such a state of matters may not long exist.]
55 (P. 461.) [I think we might call the whole class cam trains, under which the click-trains and slider-cam trains would come as special cases. The latter bear to the cam-trains the same relation that (Ca'P- 1 -) bears to (4.)
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