same may be said of both gearing and belts, for both are better servants in every way if so protected. The chains used are similar in construction to those fitted upon bicycles, and are either of the 'block' or 'roller' variety. In the former (see fig. 4) the side links, c, c, c, are connected by solid blocks of
_0222a.jpg)
Fig. 4
metal, a, a, a, through the ends of which the connecting pins, b, b, b, pass, these pins turning slightly in their bearings in the blocks as they pass round the chain wheels. In the latter shown in fig. 5 the blocks are replaced by connecting plates a, a, a, and upon the cylindrical separators connecting them
_0222b.jpg)
Fig. 5
small cylinders or rollers, b, b, b, are fitted, which roll into and out of the chain-wheel teeth as they come round. As a rule, unless some special provision is made for thorough lubrication of the connecting pins of the blocks, roller chains are usually found to run with the greater smoothness and quietude. In addition to these methods we have yet another which has been
