A Jack-of-All-Trades.
Compressed air readily moves liquids as masses; it as easily impels them as particles. A lady’s toilet table usually displays an atomizer. Its rubber bulb, sharply squeezed, emits a tiny stream of perfume as a quick air blast breaks a drop of liquid into spray. Magnify this apparatus and you have a painting machine for freight and passenger cars, fences, and out-buildings. Driven as it is with projectile force the pigment penetrates further than if laid on by hand, reaching crannies and crevices which evade a brush. On the same principle Hook’s spraying machine sends Bordeaux mixture into the foliage of an orchard, or delivers a solution of carbolic acid upon the floors, walls, and ceilings of a hospital or a sick-room. Strengthen such a blast and you can elevate, dry, and aerate grain, or lift the culm from a coal heap to a furnace, and then discharge the ashes as they tumble from a grate. Where stretches of water are sandy and muddy, compressed air dredges a channel by stirring up deposits at the bottom.