186 REDUCING ACTION OF METALLIC CALCIUM, ETC. DISCUSSION. Dr. R: Seligman hoped the authors would try the reducing effect of calcium hydride on alumina. There was, he believed, a French patent for preparing calcium hydride by absorbing hydrogen in molten calcium as opposed to the method described by the authors of maintaining the calcium in solid form for this purpose. Dr. Perkin, in reply, said that the authors would certainly try to reduce alumina with calcium hydride and with calcium. (This has since been done, and described in the paper as it passed through press.) The patent referred to in the paper was that of the Elektrochemische Werke, Bitterfeld (D.R.P. 188,570, 1907). According to this patent hydrogen gas is led into molten calcium. But the calcium hydride as obtained from Bitterfeld has not the appearance of having been made in this manner, because the form of the original rods is still retained in the calcium hydride.