half is a yoke for securing the hand shifting lever to the sliding sleeve.

Finally, there is a balance weight to counterbalance the lever and toggle and this prevents the centrifugal force from throwing the clutch in gear when it is running at a high speed. A longitudinal cross

B,

A, A Lengthwise Cross Section View of the Clutch. Transverse Cross Section View of the Clutch. C, The Clutch on Adjacent Shafts.

section of the clutch is shown at A in Fig. 74, a transverse cross-section of it is shown at B, and the clutch complete at C.

For small engines the clutch, which is also used

for a pulley, is worked by a hand wheel as shown at A in Fig. 75, but for larger engines it is operated by a lever, as shown at B.

Split Friction Clutches.-A split friction clutch is made in halves so that it can be put on the adjacent ends of the lengths of a line of shafting already in place, and can be readily installed with

A, Flywheel Hand Type of Friction Clutch. B, Flywheel Lever Type of Friction Clutch.

out taking down the shaft or disturbing any of the equipment upon it. Then again, it affords the greatest ease in taking off old parts and putting in new parts should any repairs or renewals be neces

Magnetic Clutches.-This type of clutch is constructed on the same general principle as the one 'For friction clutches of this type write A. & F. Brown, 79 Barclay Street, New York.

described for mobile engines. It is chiefly used for stationary power installations where electric generators or converters are to be started up and which must not too greatly disturb the load.1

'For magnetic clutches write Cutler-Hammer Clutch Co., Milwaukee, Wis.

CHAPTER XI

THE KIND OF AN ENGINE YOU WANT

There are many makes of internal combustion engines on the market and the kind you want will depend very largely on what you intend to use it for and the conditions under which you are going to run it.

There are, however, a few considerations in buying an engine that are fundamental and which if you are looking for service and economy at the same time you ought to know about, for if you buy one haphazard of the first make you come across you will stand a very slim show indeed of getting a good one at a fair price.

Small versus Large Concerns.-Far be it from me to want to knock the small manufacturer but to buy the best gas engine that can be made and get a guarantee that is backed up by something that looks like real responsibility you have simply got to buy an engine of a big maker or of a house of recognized financial standing.

When you buy an engine of such a concern and anything goes wrong with it you will have far less trouble in getting the dealer to make good in ad

justing the matter. Not only this but all up-to-date engines are built on the interchangeable plan, as I have mentioned before, and if you are dealing with a big company you can get a repair part in the shortest possible time because they always keep a large stock of replacements on hand.

Further, all big concerns have branch offices in many of the larger cities in the United States and so wherever you live you will have one of these service stations close at hand and this is a very great convenience. Finally, a lot of the smaller makers come and go and if you have one of their engines and they go out of business the only way you can get a repair part is to have it made to order, and this will sometimes run your replacement part into big money.

And another thing, don't make the mistake of buying an engine of some obscure maker because you can get it a deal cheaper than you can get one of the same horsepower of a well-known maker. If big concerns charge more for their engines you can depend on it that a good engine built to stand the test of time and the stress of duty simply can't be built for a lower price. Shoddy costs less in the beginning, but it can't compete with wool for wearing qualities.

Finally, every large manufacturer maintains an experimental laboratory where all new devices are tested out by experts before they are ever put on the engines they sell.

In order to buy a cheap make of engine second