An excellent brake for very large cranes is Matthew's hydraulic brake, in which water is passed from end to end of cylinders fitted with reciprocating pistons, cooling jackets being provided.
The Mad river is made to furnish good water-power by means of a hydraulic canal which takes its water through the city, and Dayton's manufactures are extensive and varied, the establishments of the National Cash Register Company employing in 1907 about 4000 wage-earners.
First, if the skeleton which it forms is continuous, then its planes of junction with the metallic matrix offer a path of low resistance to the passage of liquids or gases, or in short they make the metal so porous as to unfit it for objects like the cylinders of hydraulic presses, which ought to be gas-tight and water-tight.
Since then the hydraulic press has practically completely superseded all other appliances used for expression, and in consequence of this epoch-making invention, assisted as it was later on by the accumulator - invented by William George (later Lord) Armstrong in 1843 - the seed-crushing industry reached a perfection of mechanical detail which soon secured its supremacy for England.
Brick, tile, sewer-pipe, and hydraulic cement are manufactured, and there are railway repair shops.
The hydraulic crane has a great advantage in possessing an almost ideal brake, for by simply throttling the exhaust from the lifting cylinder the speed of descent can be regulated within very wide limits and with perfect safety.
Hence, in modern installations, the first expression of those seeds is carried out in so-called cage (clodding) presses, consisting of hydraulic presses provided with circular boxes or cages, into which the meal is filled.
The exhauster is practicall y a rotary gas pump which serves the purpose of drawing the gas from the hydraulic main through the condensers, and then forcing it through the purifying vessels to the holder.
The environs of Creil (Oise) and Chteau-Landon (Seine-et-Marne) are noted for their freestone (pierre de taille), which is also abundant at Euville and Lrouville in Meuse; the production of plaster is particularly important in the environs of Paris, of kaolin of fine quality at Yrieix (1-Jaute-Vienne), of hydraulic lime in Ardche (Le Teil), of lime phosphates in the department of Somme, of marble in the departments of HauteGaronne (St Beat), Hautes-Pyrnes (Campan, Sarrancolin), Isre and Pas-de-Calais, and of cement in Pas-de-Calais (vicinity of Boulogne) and Isre (Grenoble).
That for the thin-walled water mains must combine strength with the fluidity needed to enable it to run freely into its narrow moulds; that for most machinery must be soft enough to be cut easily to an exact shape; that for hydraulic cylinders must combine strength with density lest the water leak through; and that for car-wheels must be intensely hard in its wearing parts, but in its other parts it must have that shock-resisting power which can be had only along with great softness.