-------+-----------+------------+---------+---------+--------------+--------------+ Castner's New Method for Producing Sodium. This new method, heretofore mentioned by us, is now being successfully worked in London, and is thus described in _Engineering_: Up to the present this novel method of manufacture has been kept rather secret, but now, owing to the success achieved by a plant erected and worked on a commercial scale, we are enabled, through the courtesy of Mr. H. Y. Castner, to lay before our readers an outline sketch of the method of operation which is followed, and which we have seen carried out with success at his works, 65 Belvidere Road, Lambeth. Few persons outside of the chemical profession are aware of the commercial existence of the metal sodium or of its uses, and even among those following that profession but little is known, except that it is used in the manufacture of aluminum, and is very expensive. Much has lately been published in various scientific journals throughout the world upon the subject of alleged new processes, whereby that highly interesting metal--aluminum--might be cheaply produced without sodium, and thus be made to take in the commercial world a place to which its varied valuable properties entitle it. So far nothing has resulted from these numerous so-called discoveries, and at the present time the only process in use whereby aluminum can be produced is that devised by and due to Deville's ingenuity.[1] This process has been called the sodium process, apparently to distinguish it from others, but seeing that it is the only process which has ever proved practical, it is somewhat of a mystery why it needed to be so distinguished. [1] The Cowles electric smelting process, heretofore described by us, has only produced aluminum alloys as yet, and it is doubtful whether it can be made to do more than this. The late Dr. Walter Weldon, in a paper read before the Society of Chemical Industry a few years ago, clearly resolved the great question of cheaply producing aluminum, and showed by argument that this end was only to be gained in either of the two following directions, namely, first, by the production of cheap sodium and the employment of Deville's process, and second, by the discovery of a substitute for sodium, which has hitherto given to aluminum its excessive cost in production. After twenty-five years of research by some of the best scientists of the present age, no substance has been found that will replace sodium, and although every known substance has, at various times, been proposed, none has been successful. So discouraging has been the research, that those familiar with the subject have almost abandoned hope of ever seeing aluminum cheaply manufactured by chemical processes, believing also that Weldon's first proposition was an impossibility.