1366
JOURNAL 01' CHEMICAL EDUCATION
J U LY .
1931
with zeolite. The openings of the tubes (C and D) which serve as inlets into these bottles should be protected with brass screening to prevent clogging. The apparatus shown in the photograph permits switching the flow of hard water from the first softener to the second when the former has "gone hard." However, operation must be suspended when regeneration of one or both softeners becomes necessary. A slight modification in connections (shown in the diagram) makes it possible to revive either softener while the other is in operation. For the reviving fluid we have found i t best to use a saturated brine solution. This is best prepared in advance by allowing concentrated salt solution to stand for several days in contact with excess solid salt. A rapid, easily visible test for hardness is desirable for demonstration use. For this purpose the writer has found soap solution satisfactory. A little hard water drawn a t K curdles the soap; soft water drawn a t H does not. This simple test also serves to indicate the eventual exhaustion of the zeolite and its subsequent revival. The time necessary to complete the exchange of metals which is the essential feature of this process will vary according to the "hardness" of the water and the amount of sand employed. Rates of flow should be adjusted accordingly. Pedagogical Considerations The instructor may employ this demonstration, not only as an explanation of one of the every-day applications of chemistry, but as an occasion for stressing or reviewing the law of mass action and the characteristics of reversible reactions in general.
Geologist Believes U. S. Could Produce Radium at Foreign Price. It would be possible for the U. S. Bureau of Mines to manufacture one gram of radium from vanadium-uranium-radium ores in Colorado and Utah a t a cost comparable t o the price for which radium can be purchased from the Belgian Congo. Dr. G. F. Loughlin of the Geological Survey has made a survey of the mines in these states and has reported to the Hourc Committee an Mines and Mining. I n the mines in question, uranium used to be the product sought, but the ores arc worked chiefly today for vanadium. Uranium and radium could be extracted from the vanadium ores as by-products, so that the chief cost of mining and exploration could be borne by the vanadium production. Dr. Loughlin suggests the addition of uranium units t o existing vanadium plants, or the building of new mills for the extractionof both vanadium and uranium. Of late years uranium has been mined only by gouging out small quantities t o sell t o manufacturers of radium belts and radioactive waters. Although warning that his estimate is only a guess, Dr. Loughlin says he believes that radium could be extracted from these ores a t a cost of $50 a milligram. The price of radium from the Belgian Congo is now about %fiO.OOO per gram.-Science Service
