monument to moneyed kings.

The hydraulic piston compressor has one solitary advantage, and that is,
it has no dead spaces. It was conceived at a time when dead spaces were
very serious conditions--were positive specters! Valves and other
mechanism connected with the cylinder of an air compressor were once of
such crude construction that it was impossible to reduce the clearance
spaces to a reasonable point, and, furthermore, the valves were heavy
and so complicated that anything like a high speed would either break
them or wear them out rapidly, or derange them so that leakages would
occur. But we have now reduced inlet and discharge valves and all other
moving parts connected with an air cylinder to a point of extreme
simplicity. Clearance space is in some cases destroyed altogether by
what is, as it were, an elastic air head which is brought into direct
contact with the piston. All this reduces clearance to so small a point
that it has no influence of any consequence. The moving parts are made
extremely simple, even arriving at a point where inlet valves are opened
and closed by their natural inertia. Mr. Sturgeon, of England, has
applied a most ingenious and successful inlet valve, which is opened and
closed by the friction of the air piston rod through the gland. We have,
therefore, reached a point at which high speed is made possible.

Long-stroke air compressors are evidently objectionable on the basis of
greater expense of construction. All the parts must be larger and
heavier. The fly wheels are increased enormously in diameter and weight,
and the strength of bearings must be enlarged in proportion. It is
difficult to equalize power and resistance in air compressors with long
strokes. The speed will be jerky, and when slow, the fly wheel rather
retards than assists in the work of compression. This action tends to
derange the parts and makes large bearings a necessity. The piston in a