testing pipe joints, fuel containers, etc. The illustration at Fig. 43 shows a portable, electrically driven power pump suitable for public or private garages and repair shops. It is simple and compact in construction and as it is mounted on a wheeled base it can be easily drawn around the building or outside to the curb. A tank, 12 inches long and 6 inches in diameter, into which the pump discharges, prevents condensation and oil from entering and injuring the tire.

It is said that the pumping action is very rapid, as a 35 x 4 inch tire can be pumped from flat to 70 pounds pressure in one and onehalf minutes. The motor is a Westinghouse, one and a quarter horsepower capacity, designed to operate from the lighting circuit and may be secured in any of the voltages commonly used.

A group of air compressors of different designs is shown at Fig. 44. That at A, is a powerful, hand operated double pump suitable for those garages and repair shops not provided with mechanical

power. It is operated through a lever which is sufficiently long so it can be worked by one or two men standing upright. The form at B is a substantial power-driven compressor of large capacity having an oscillating cylinder. This type is used only in large repair shops where it is necessary to use a large air tank which must

be constantly filled. The air pump at C, has a vertical cylinder and is driven from an electric motor by means of a spur pinion on the armature shaft which meshes with a large gear on the pump crankshaft. This is attached to a substantial iron base and is intended to be bolted to the floor. A small portable power pump for use on the bench is shown at Fig. 44, D. This also is driven

by an electric motor, the power being transmitted from the armature by belt connection to the rim of a large flywheel-pulley attached to the crank disc of the pump. The outfit at E is similar in operation to that shown at C, except that a two cylinder air compressor is used. This is practically the same in general construction as the other forms illustrated, except that the use of two cylinders makes for a more steady flow of air.

A complete air compressor outfit provided with automatic regulating means and an apparatus to distribute air at the curb is shown at Fig. 45. This enables automobile owners to secure a supply of air without having to drive the car into the garage or dragging a portable air compressor outfit across the sidewalks. The accompanying diagram clearly shows the arrangement of this outfit. A tank is buried in the ground and this connects with the compressor outfit located in the basement. The lid of the curb box is flush with the sidewalk and in a few inches from the curb. The user raises the lid, takes out the hose and when the operation of tire inflation is complete, the hose returns to the box automatically when it is released. The air compressor installation consists of a reservoir or tank in the basement, an air compressor driven by an electric motor and a control panel. When the air pressure in the tank reaches a certain predetermined amount, an automatic switch breaks the circuit and the motor ceases to drive the pump. As soon as the pressure falls below the minimum allowable, the automatic switch again functions to close the circuit and start the pump going. In addition to the pipe leading to the curb box a branch pipe may be run to the garage interior and to the repair shop as well.

Liquid Fuel Storage. The problem of liquid fuel storage is an important one for garages or repair shops, especially in cities where the municipal regulations pertaining to the storage of volatile hydrocarbons are severe. If the fuel is to be used only for shop purposes, either of the fuel storage systems shown at Fig. 46, A and B, will prove practical. That at A is the hydraulic system in which the gasoline stored in an underground tank is forced out by displacement, water flowing into the tank from the city main. The outfit at B also includes an under

ground tank which is placed outside of the walls of the building, but the gasoline is drawn from the tank by a plunger pump. Where gasoline is sold to passing motorists two appliances that will promote quick service are shown at Fig. 46, C, and D. That at C, is a box designed to be placed outside of the garage or repair shop near the door or driveway so that cars do not need to run into the garage to be filled. This serves merely to support

a measuring pump drawing fuel from an underground tank and hose which will extend from the pump to the fuel container of the car. The outfit shown at D, consists of a rectangular tank mounted on wheels and having the usual form of measuring pump. This tank will hold several barrels of fuel, can be moved easily

from place to place and the measuring pump insures that the liquid will be dispensed in proper quantities and without waste.

The principle of action of the hydraulic fuel supply system is shown at Fig. 47, A. The various parts comprising the assembly are clearly outlined. When it is desired to draw out gasoline it is merely necessary to open the water control valve which permits water to flow into the tank to displace the fuel. At Fig. 47, B, the