Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: smoothly ; they should not snap or be forced out of their proper path. The less noise the cog wheels make the more noiseless the valves, cams, and levers of the regulating gear work, the less the machine hisses and puffs, the less the neighborhood of the motor smells of gas and burned oil, so much the better is the motor constructed and run, and so much more agreeable will it be to have to do with it. When an opinion has thus been tormed as to the solidity of construction and the ease of running there remains the question of economy—that is, the gas required by the motor. For this purpose let the belt be thrown off and observe the throwing in and out of gear of the controlling mechanism while the motor runs empty. Nowadays it is to be expected that in such case for one power stroke six omissions will occur, and thereof the gas consumption for no load should not be morethan I-7th of that required for full power. The number of revolutions, first for no load, then for full load for the same period of time, about 5 minutes, should be taken. With no load the machine runs taster than when loaded ; the difference between the total revolutions should not be more than 5 per cent. The loading of the motor can be done by pressing a wooden beam against the fly-wheel, the full load in which no misfires occur should not be reached by these means. It is here understood the regulation of speed is by periodic full power. There are other methods by which the regulation under variable load is effected, but for no load these are not so economical, while they give more uniform rate. Now read of the gas consumption observed from the dial of the gas meter for a period of about five minutes. Good gas motors should, if the exhaust pipe is not too long or too small, consume for no loa...