It was when this question had assumed a most formidable, importance, that the principle of using steam in compound steam engines had engaged the careful consideration of the most eminent engineers of this and other countries; its adjustment to the Duplex pumps was made, and while it was easily done, owing to their peculiar construction, its application produced a most wonderful result in their working, and their speedy introduction for water works use.
Note.—At this time the man who had invented and built the little steam pump for the canal boat, who had watched its growth and development, supplemented one device after another to help it on through the trial period of its existence, had merged it at last into the dual or duplex stage of its advancement, had added to it the compound feature, had seen it expanding in size and importance until, growing up and out of the day of small things, it had come to take its well-earned place alongside those old and massive machines whose invention and origin was lost amid the musty records of the past—it was, at this time, and of which any man might well have been proud, that his lifelong labors came to an end Dec. 18., 1880, at the Everett House, New York City.
ELEMENTARY
HYDRAULICS
ELEMENTARY HYDRAULICS.
There are three physical states or conditions of matter, which are the solid, liquid and gaseous, which in this connection apply to Ice, Water and Steam. A solid offers resistance both to change of shape and to change of bulk.
A Fluid offers no resistance to change of shape. Again fluids can be divided into liquids and vapors or gases. Water is the most familiar example of a liquid. A liquid can be poured out in drops while a gas or vapor flows in a stream or streams.
Gas is a term at first used as meaning the same as the name air, but is now restricted to fluids supposed to be permanently elastic, as oxygen, hydrogen, etc., in distinction from vapor such as steam which become liquid upon a reduction of temperature.
It is important to note that experiment proves that every vapor becomes a gas at a sufficiently high temperature or low pressure, while, on the other hand, every gas becomes a vapor at sufficiently low and high pressures. In present popular usage the term gas applies to any substance in the aeriform elastic condition.
Hydraulics is that branch of science or of engineering which treats of the motion of liquids, especially of water and of the laws by which it is regulated.