Show Device Converts Auto Cylinder Into Air Pump A new device that can crin be screwed Into the spark plug hole holc of at one of the autos auto's cylinders turns that cylinder cylInder cylinder cyl cyl- inder into an alt all pump that will produce produce pro pro- duce two and a half cubic feet of free tree air per minute This much air airIs airIs airis Is sufficient to spray spra oil paint germicide germicide germi germi- cide Insecticide and liquids says cays Popular Science Monthly On the down stroke of at the piston In the cylinder to which the device Is fitted the piston sucks In outside air through a a spring operated valve On the up stroke this valve closes and another opens allowing the air to flow into a storage tank or Into the pipe leading to the spray equipment equip equip- ment If It more air is needed than can be obtained from one cylinder In this way two of or the devices can be used at the same time so as to double the output It Is designed to too work worl at an engine speed equivalent to a a. road speed of at 20 miles mUes an hour |