Turbine pumps of the Forneyron type have an outward flow; but another form, invented also by a Frenchman, Jonval, has a downward discharge, and others are oblique, double, combined turbine, rotary, and centrifugal, embodying similar principles. The term _rotary_, broadly speaking, includes turbine and centrifugal pumps. The centrifugal pump, invented by Euler in 1754, was taken up in the nineteenth century and greatly improved. In the centrifugal pump of the ordinary form the water is received at the centre of the wheel and diverted and carried out in an upward direction, but in most of its modern forms derived from the turbine, the principle is adopted of so shaping the vanes that the water, striking them in the curved direction, shall not have its line of curvature suddenly changed. Among modern inventions of this class of pumps was the “Massachusetts” of 1818 and McCarty’s, in 1830, of America, that of some contemporary French engineers, and subsequently in France the Appold system, which latter was brought into prominent notice at the London Exposition of 1851. Improvements of great value were also made by Prof. James Thompson of England. Centrifugal pumps have been used with great success in lifting large bodies of water to a moderate height, and for draining marshes and other low lands. Holland, Germany, France, England and America have, through some of their ablest hydraulic engineers and inventors, produced most remarkable results in these various forms of pumps. We have noted what has been done at Niagara with the turbines; and the drainage of the marshes of Italy, the lowlands of Holland, the fens of England and the swamps of Florida bear evidence of the value of kindred inventions. That modern form of pump known as the _injector_, has many uses in the arts and manufactures. One of its most useful functions is to automatically supply steam boilers with water, and regulate the supply. It was the invention of Giffard, patented in England in 1858, and consists of a steam pipe leading from the boiler and having its nozzle projecting into an annular space which communicates with a feed pipe from a water supply. A jet of steam is discharged with force into this space, producing a vacuum, into which the water from the feed pipe rushes, and the condensed steam and water are driven by the momentum of the jet into a pipe leading into the boiler. This exceedingly useful apparatus has been improved and universally used wherever steam boilers are found. This idea of injecting a stream of steam or water to create or increase the flow of another stream has been applied in _intensifiers_, to increase the pressure of water in hydraulic mains, pipes, and machines, by additional pressure energy. Thus the water from an ordinary main may be given such an increased pressure that a jet from a hydrant may be carried to the tops of high houses.