In connection with pumping it may be said that a great deal has been discovered and invented during this century concerning the force and utilisation of jets of water and the force of water flowing through orifices. In the art of mining, a new system called _hydraulicising_ has been introduced, by which jets of water at high pressure have been directed against banks and hills, which have crumbled, been washed away, and made to reveal any precious ore they have concealed. To assist this operation _flexible nozzles_ have been invented which permit the stream to be easily turned in any desired direction. Returning to the idea of raising weights by hydraulic pressure, mention must be made of the recent invention of the _hydraulic jack_, a portable machine for raising loads, and which has displaced the older and less efficient screw jack. As an example of the practical utility of the hydraulic jack, about a half century ago it required the aid of 480 men working at capstans to raise the Luxor Obelisk in Paris, whilst within 30 years thereafter Cleopatra’s Needle, a heavier monument, was raised to its present position on the Thames embankment by four men each working one hydraulic jack. By the high pressures, or stresses given by the hydraulic press it was learned that cold metals have plasticity and can be moulded or stretched like other plastic bodies. Thus in one modification a machine is had for making lead pipes:--A “container” is filled with molten lead and then allowed to cool. The container is then forced by the pump against an elongated die of the size of the pipe required. A pressure from one to two tons per square inch is exerted, the lead is forced up through the die, and the pipe comes out completed. Wrought iron and cold steel can be forced like wax into different forms, and a rod of steel may be drawn through a die to form a piano wire. By another modification of the hydraulic press pipes and cables are covered with a coating of lead to prevent deterioration from rust and other causes. Not only are cotton and other bulky materials pressed into small compass by hydraulic machines, but very valuable oils are pressed from cotton seed and from other materials--the seed being first softened, then made into cakes, and the cakes pressed. If it is desired to line tunnels or other channels with a metal lining, shield or casing, large segments of iron to compose the casing are put in position, and as fast as the tunnel is excavated the casing is pressed forward, and when the digging is done the cast-iron tunnel is complete. If the iron hoops on great casks are to be tightened the cask is set on the plate of a hydraulic press, the hoops connected to a series of steel arms projecting from an overhanging support, and the cask is pressed upward until the proper degree of tightness is secured.