Page:Miscellaneous Papers on Mechanical Subjects.djvu/134

 were making panelled doors at the rate of 100 per day.

Portable sawing machines, driven by horse-power, are commonly used for sawing up logs of wood for fuel, particularly at the various stations on the railroads, where the wood intended for the consumption of the locomotives is stored in piles.

The "horse-power machine" consists of a stout frame supporting a railway about 7 feet long, on which run the rollers of an endless travelling platform. The axles of the rollers are of iron, ⅝ in. diameter, stretching across the rails, and are connected together by a series of links, each about 12 inches long, so as to form an endless chain, which passes over a fixed segment at one end and the chain wheels at the other. The travelling platform is made by planks of wood about 12 inches broad, 1¼ inches thick, fastened transversely to the endless chain. It is inclined at an angle of about 7° to the horizontal line, and the horse being placed on the platform, pushes it backward from under him, which causes the chain wheels at the end of the frame to revolve, and the motion thus obtained is conveyed to the circular saw or other machine required to be driven. Some horse-power machines are made to admit two horses abreast. They are found very useful to farmers; when