Cement

See CEMENT, CEMENT TESTS, and HYDRAULIC LIMESTONE. large plants two of them are used, the one with lighter load filling the pre chamber, and the heavier one being connected to the latter only when it is filled. A notable saving in pumping power and in time is thus effected. Pre ures as high as 2,500 lbs. to the sq. in. are in use for the heavier accumulator. Hydraulic forging proce es do not expel cinder from welded metal as well as hammers, nor do they restore impaired density to the bar as well as percu ive proce es. See FORGING OF METALS.