in reality a very important matter and too much care cannot be used in selecting the best oil for the motor and, when once found, adhering to one brand and not continually changing. Some engines require a much heavier oil than others and a new motor will usually work better on a light oil than an old or worn engine. In hot weather, also, a heavier oil can be used than in cold weather, for even the best of gasolene-engine cylinder oils will thicken up in cold weather. Many motors in which the rings or cylinder are so badly worn as to lose compression will operate very successfully if fed a heavier grade of oil, and in two-cycle motors a good supply of heavy oil or grease on the bearings results in better base compression and more efficient service. Machine oil or steam-engine oils should never be used in a gas-engine cylinder. The terrific heat in these motors will ignite any but oils made especially for the purpose, and poor or low-grade oils will form excessive carbon deposits. Oil is cheaper than motors and the very best on the market is none too good for the poorest motor built. Machine oil is very good for exterior use and for that purpose is superior to cylinder oil, but even where so used it should be of a high grade that will not gum or stick.

Greases used in grease cups and transmissions should be selected with as much care as the oil, for a poor grease will gum and stick, while a grease containing any grit, dirt, or foreign matter will soon cut out and ruin bearings. Some greases on the market are more like soft soap than grease; they are stringy, sticky, elastic compounds and are unfit for any use. A good

grease should be smooth, clear-colored, clean and soft in any weather. The hardness or softness of a grease used should be determined by trial, and any reputable manufacturer of oils and greases will gladly furnish samples of the various grades. The grease used should be heavy enough so that it will not run and spread, and should be soft enough to feed easily and regularly through the grease cups. The oil used should always be strained before being placed in the lubricators, and if at any time the oil is found to contain any trace of grit or dirt it should be at once discarded and all oilers, oil-pipes, and bearings thoroughly cleaned with kerosene and gasolene before using new oil. The amount of oil to be fed to any motor, or to any part of a motor, depends largely upon the make, the age, the care, and the work of the engine as well as upon the grade of the oil. A new engine should be given a liberal supply of oil until well broken in, when the supply can be cut down somewhat. Too much oil will cause soot and carbon, but too little will result in wear and cutting, and of the two evils it is far better to use too much than too little.

When stopping the motor the oil should always be turned off, as otherwise an excess may get into the cylinder. If a mechanical force-feed oiler is used it will take care of itself in this matter. An excess of oil is readily determined by smoke from the exhaust, and a smell of burning or hot oil. If the proper amount of oil and a correct mixture of fuel are being used, the exhaust will be almost colorless or of a faint bluish tint. If too much oil is used the blue will increase until a dense bluish or yellowish smoke issues from the exhaust. If

the mixture of air and fuel is too rich—that is, contains too much gasolene-the exhaust smoke will be either black or dense and white with a sharp, choking, pungent odor.

Most engine-makers furnish directions as to the proper amount of oil to be fed the various parts, and these should always be observed. Few moving parts of a motor require less than six drops per minute and few need more than fifteen or twenty, but in winter the adjustment of the lubricators must be altered to suit weather conditions in order to supply the proper amount of oil.

The installation of a gasolene motor seems a very easy matter, but really many excellent engines fail to give proper service or satisfaction owing to careless or improper installation. In vehicle motors this fault is not common, as the makers of motor-propelled vehicles install the motors themselves and usually see that it is properly done. Stationary motors that are manufactured mounted on trucks, frames, or skids are also usually free from faulty installation, but stationary motors set up by the purchaser and especially marine motors, are often so badly installed that it is surprising that they work at all.

The first consideration in installing a motor is the bed. For stationary engines the character and material of the beds depend largely upon the space available, the material at hand, and the location. Brick, stone, cement, and timbers all make good beds, but perhaps the most satisfactory method is to make a good solid bed of concrete in which timbers should be embedded

just far enough apart so that the bed-plate of the motor may be bolted to them. The timbers should be of ample size, and, to hold them firmly in the cement or concrete, spikes or bolts should be driven into them at intervals before burying in the cement. The cement bed, as well as timbers, should be smooth and level, but a space under and around the motor may be made depressed to catch any water or oil, and drains may be led from this. If after finishing the bed the timbers are found out of level, they may be easily levelled up by thin shims, or bits of wood or metal, placed between them and the engine bed-plate. In placing the motor care should be taken to see that it is so placed as to afford the greatest facility in reaching any and all parts of it and at the same time it should occupy as little space as possible. The engine may be bolted to the bed either by lag-screws through the holes in the bed-plate and well set into the timber, or by bolts put through the timbers before embedding. The bed-plate may then be set over these bolts and held in place by nuts. In either case washers should be placed between the head of lag-screw and engine bed-plate or underneath the nuts. The screws or nuts should be screwed in gradually, first at one corner, then at another; and one bolt or screw should never be fully tightened up before setting up another, as this will often bring an unequal strain and cause a crack or break in the engine bed-plate.

For large stationary motors the beds should be made. of solid concrete or bricks set in concrete, and on top of this a flat heavy slab of flagstone or granite should be placed. The bed should be carried down to hard pan

or at least below the frost line, and if the motor is to be placed above the ground floor of a building the bed should have solid iron columns running down to the ground. If this is not possible it should be placed as near the side or corner of the building as possible, and the portion of the floor supporting the bed should be firmly

and rigidly braced. Never bolt an engine directly to floor timbers or planks. In making a heavy concrete bed the sides should slope slightly and the bolts for holding down the engine should be well set in the concrete. A good method is to insert the bolts through iron pipe with a nut at the lower end, and the whole