the cock. A vent pipe extends from the lower compartment to the air in order to prevent the accumulation of any pressure due to gas generation from vaporization of the volatile liquids. The

upper portion of the container and the pipe connections are also provided with cleanout plugs.

Another form of separator is shown at Fig. 42. This is marketed to meet the requirements of the fire and building departments of New York City and is known as the Paragon Separator. It is said that the best position for this device is near the side walk and

under the floor with a hand pump projecting through the floor. The waste water containing gasoline and oil enters the branch floor drain and flows into a sand box where all solid matter is extracted. From this point the liquid flows through a screen into a U-shaped container and then out through a discharge pipe into the street sewer. Inside the main portion of the U-shaped container is the cylindrical oil chamber in which the volatile liquids are collected.

Fig. 42. Another Form of Scparator for Garage or Repair Shop Use.

As before stated, these are lighter than water and will float on the surface and thus enter the oil chamber through a suitable opening at the back of the cylinder. An indicator with a ball float shows the level of liquid in the oil chamber and when a sufficient quantity is indicated it may be drawn out by a hand pump. Two air vents are provided, one running to the roof for taking out the impure air, while another one runs to the sidewalk to let in fresh air which is heavier than that saturated with hydrocarbon vapor, thus driving it

out. The sand box is placed in a convenient position so to afford ready access when new filtering material is needed. Relief pipes are provided in both the U-shaped container and in the oil chamber to prevent the accumulation of any pressure in either of these portions of the separator.

Air Compressor Types.-All up-to-date repair shops, especially

Fig. 43.-Portable Electrically Operated Air Compressor Outfit.

if they are an adjunct to a garage, or if they cater to tire repair work, have some power-driven source of compressed air. A blast of air has many uses besides that of filling pneumatic tires, as it can be used for blowing out loose carbon particles from the combustion chamber or light chips and steel fragments from gear boxes or rear axle housings. The air blast may also be used for cooling heated steel gradually when annealing it and can also be employed for

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