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To Obtain Phosphoric Acid

This is obtained by heating nitric acid in a tubulated retort connected with a receiver; 3919. To Remove the Odor from Carbolic Acid. It may be interesting to know of a method which will entirely remove this odor, substituting for it a delicate trace of geranium leaves, which may, perhaps, be improved upon by adding a few drops of that oil. The process, as recently published by Professor Church, consists in pouring 1 pound small fragments of phosphorus are dropped of the best carbolic acid of commerce (the into the acid, singly and at intervals. As white crystallized) into 2 gallons cold distilled soon as the phosphorus is dissolved, the heat water, taking care not to permit the whole of is increased, and the undecomposed acid disthe acid to enter into solution. With a good tilled off. The residuum is then evaporated sample, if, after shaking repeatedly at inter- to a syrupy consistence, and forms the phosvals, between 2 and 3 ounces of the acid remain at the bottom of the vessel used, this will be a sufficient residue to hold and contain all the impurities; with bad samples, less water must be used, and more acid. The watery solution is to be syphoned off, and filtered, if necessary, through fine filtering paper, till phoric acid of commerce.

3922. To Obtain Hydrated or Glacial Phosphoric Acid. Phosphoric acid (see last receipt) is gradually heated to redness in a platinum crucible, and the glacial acid obtained by evaporation. Solid hydrated or glacial phosphoric acid contains 89 per cent. perfectly clear. It is then placed in a tall of real acid, and 11 per cent. of water. It is cylinder, and pure powdered common salt a highly deliquescent, glassy-looking subadded, with constant agitation, till it no longer stance, very soluble in water, yielding a soludissolves. On standing for a time, the greater tion exhibiting powerful acid properties. Its part of the carbolic acid will be found floating concentrated solution has nearly the same as a yellow oily layer on the top of the saline properties as the solid acid; its dilute solution liquor, and merely requires to be removed to is not poisonous, and does not precipitate be ready for use. As it contains 5 per cent. albumen. (Cooley.) or more of water, it does not generally crys-