November, 1924
INDUSTRIAL A N D ENGINEERING CHEMISTRY
these industries 150,000 tons of potash annually. We know how to recover it and we know the nature of the benefits and profit that will accompany its recovery. Armed with these facts it is our purpose to do all that we can to bring about the development of this by-product potash industry to its logical extent. What we have in mind with respect to this development may be illustrated by an analogous conservation already realized which makes available for American agriculture great quantities of that other essential of present fertilizer practice-namely, ammonium sulfate. The value of this product as a by-product of the coking industry has now become so well recognized and its production so well standardized that the coking of coal witho u t by-products has almost disappeared and the yield of byproduct ammonia has advanced from nothing to a yearly output of over 600,000 tons. America now exports ammonium sulfate where a few years ago she imported a considerable portion of her requirement. What has happened in the coking industry it is our hope to see duplicated in the blast furnace, the cement, t h e sugar, and the distillery industries. The affirmative results already obtained in governmental and private researches convince us that this is an entirely reasonable expectation. Potash yielded from these industries would enjoy tH@additional advantage of economical distribution, as it would be produced for the most part within agricultural regions. Long freight hauls to market and the great expense incurred thereby would be avoidable. Where is the logic in going to Europe for our potash while we are throwing away as a waste product of our industries our practical requirements?
THE POTASH MINERALS In certain mineral deposits already surveyed are further quantities of potash, enormous in extent but awaiting before be-
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coming available a better appreciation of improved methods of recovery. The greensands of New Jersey, the potash shales of Georgia, the leucites of Wyoming, and the alunites of Utah contain in the aggregate inexhaustible quantities of potash, and methods of recovering it therefrom are now much nearer solution than is generally recognized. The problem again is one of by-products. In most of these raw materials aluminium is an important constituent. Great progress is being made in the development of methods of its recovery as alumina as a raw material for the aluminium industry. From such a mineral as alunite the solution of this problem will mean also the solution of the problem of the economical recovery of potash therefrom, and the same, it now appears, will prove to be the case with the potash shales, feldspars, leucites, and greensands. In present researches emphasis placed on alumina, instead of on potash exclusively as in the past, has brought the solution of the problem within sight. For some time we have known ho,w to obtain the potash. We now know how to obtain both potash and alumina and in one important instance, greensand, still other products of value. Results now in hand warrant the expectation that all of these materials can with some further research be made to yield their quota to the nation's potash supplies. Finally, the observations recorded in the Texas Panhandle showing unmistakable evidences of subterranean potash deposits convince us that in some one of these three groups of raw materials, if not in all of them, adequate quantities of potash will be produced, certainly to render the American farmer free from danger of unrestricted exploitation by foreign monopoly, if not to supply the nation with its entire requirements in respect to that essential commodity.
A Constant-Level Device for a Thermostatic Bath' By Isaac Bencowitz and Henry T. Hotchkiss, Jr. NEWYORKUNIVERSITY, NRWYORK, N. Ji.
arrangement shown a t B. Opposite the inlet is located the constant-level apparatus. The water overflows into a tube, C, which drains the tank from the top. A siphon then Large cylindrical enamelware tanks, covered with insulating carries the water from this tube over the edge of the tank felt, when equipped with suitable stirring and temperature- into a discharge tube, D. With the apparatus set up as regulating devices,2 were found to maintain a uniform tem- shown the siphon will A B perature throughout. The problem was to fit the thermo- not break, as the end stat with a proper constant water level and drainage system. of the inverted U tube Many of the most expensive and elaborate thermostats fail in rests in a small reserthis respect, and little on the subject appears in the l i t e r a t ~ r e . ~voir of water and flow e The importance of a constant level in a thermostatic is only occasioned when the head of water in C bath is self-evident. Adequate draining on hot days when the temperature of the atmosphere is above that of the is sufficient to cause a thermostat is essential, since a constant supply of cooling displacement in the 0 water must be maintained. Furthermore, to keep the water direction of D. The clear for long intervals of time, especially where the water upper tube, E, is joined becomes contaminated with rust from ironware immersed as shown to act as a in it, is an important consideration. With the device de- safety overflow. scribed herein, however, no difficulty was experienced. This apparatus is simple, compact, and easily constructed. The water supply is controlled by valve A , which allows The thermostat in this laboratory has been running satisthe cooling water to enter a t the bottom of the tank. The factorily for several months. The water is constantly water is immediately swept into circulation by the stirring drained and perfectly clear. This type of drainage is not limited to thermostats, but can be adapted to other constant1 Received September 24, 1924. level systems where the chief object is to keep the tank 7 D J. and J. J. Beaver, THIS JOURNAL, 16, 359 (1923). clean as well as to maintain a constant level. 8 Wilde, Ibad., 16, 904 (1924).
N THE: course of work in this laboratory it was necessary Itemperature to instal thermostatic baths which would maintain a of 25' * 0.005' C . for long periods of time.
