Like manganese steel, tungsten steel retains its temper even when heated to high temperatures. For this reason it is used frequently in making tools for metal-lathe work where thick slices of iron are to be cut, as even at red heat such a tool continues to cut off metal chips as readily as when kept at a lower temperature. This steel contains from 6 to 10 per cent. of tungsten, a metallic element with which we have previously made acquaintance in our studies of the incandescent lamp.
[XIV]
SOME RECENT TRIUMPHS OF APPLIED SCIENCE
Not long ago a little company of men met in a lecture hall of Columbia University to discuss certain questions in applied science. It was a small gathering, and its proceedings were so unspectacular as to be esteemed worth only a few lines of newspaper space. The very name—"Society of Electro-Chemistry"—seemed to mark it as having to do with things that are caviare to the general. The name seems to smack of fumes of the laboratory, far removed from the interests of the man in the street. Yet Professor Chandler said in his address of welcome to the members of the society, that though theirs was the very youngest of scientific organizations, he could confidently predict for it a future position outranking that of all its sister societies; and his prediction was based on the belief that electro-chemistry is destined to revolutionize vast and important departments of modern industry. A majority of the heat-using methods of mechanics will owe their future development to the new science.
In a word, then, despite its repellent name, the society in question has to do with affairs that are of the utmost importance to the man in the street. Though its members may sometimes deal in occult formulas and abstruse calculations, yet the final goal of their studies has to do not with abstractions but with practicalities,—with the saving of fuel, the smelting of metals, the manufacture of commodities. But theory in the main must precede practice—the child creeps before it walks. "The later developments of industrial chemistry," says Sir William Ramsey, "owe their success entirely to the growth of chemical theory; and it is obvious," he adds significantly, "that that nation which possesses the most competent chemists, theoretical and practical, is destined to succeed in the competition with other nations for commercial supremacy and all its concomitant advantages."
Fortunately this interdependence of science and industry is not a mere matter of prophecy—for the future tense is never quite so satisfying as the present. Vastly important changes have already been accomplished; old industries have been revolutionized, and new industries created. The commercial world of to-day owes vast debts to the new science. Professor Chandler outlined the character of one or two of these in the address just referred to. He cited in some detail, for example, the difference between old methods and new in such an industry as the manufacture of caustic soda. He painted a vivid word picture of the distressing conditions under which soda was produced in the old-time factories. Salt and sulphuric acid were combined to produce sulphate of soda, which was mixed with lime and coal and heated in a reverberatory furnace. Each phase of the process was laborious. The workmen operating the furnaces sweltered all day long in an almost unbearable atmosphere—stripped to the waist, dripping with perspiration, sometimes overcome with heat. Their task was one of the most trying to which a man could be subjected.
But to-day, in such establishments as the soda manufactories at Niagara Falls, all this is changed. A salt solution circulates continuously in retorts where it can be acted upon by electricity supplied from dynamos operated by the waters of the Niagara River. The workmen, comfortably dressed and moving about in a normal temperature, have really nothing to do but refill the retorts now and then and remove the finished product. "It almost seems," Professor Chandler added with a smile, "as if workmen ought to be glad to pay for the privilege of participating in so pleasant an occupation. At all events it is, in all seriousness, a pleasure for the visitor who knows nothing of old practices to witness this triumph of a modern scientific method."
Even more interesting, said Professor Chandler, are the processes employed in the modern method of producing the metal aluminum by the electrolytic process. The process is based on the discovery made by Mr. Charles M. Hall while he was a student working in a college laboratory, that the mineral cryolite will absorb alumina to the extent of twenty-five per cent. of its bulk, as a sponge absorbs water. The solution of this compound is then acted on by electricity, and the aluminum is deposited as pure metal. A curiously interesting practical detail of the process is based on the fact that pulverized coke remains perfectly dry and rises to the surface when stirred into a crucible containing the hot alumina solution: moreover, it rises to the surface and remains there as a shield to protect the workmen against the heat of the solution. It serves yet another purpose, as the powdered alumina may be sifted upon it and left there to dry before being stirred into the crucible. A most ingenious yet simple device tells the workman when any particular crucible is in need of replenishing. A small, ordinary, incandescent electric-light bulb is placed in circuit between the poles that convey the electric current through the alumina solution. So long as the crucible contains alumina, the bulb does not glow, because twenty volts of electricity are required to make it incandescent, whereas seven volts pass through the solution. But so soon as the alumina becomes exhausted, resistance to the current rises in the cryolite solution and, as it were, dams back the electric current until it overflows into the wire at sufficient pressure to start the signal lamp. Then it is necessary merely for a workman to stir into the solution the dry alumina resting on the surface, along with the coke that supports it. This, of course, reestablishes the electrolytic process; the lamp goes out and the coke, unaffected by its bath, rises to the surface to support a fresh supply of alumina.