Ure's Dictionary of Arts, Manufactures, and Mines; Containing a Clear Exposition of Their Principles and Practice Volume 2 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1860 edition. Excerpt: ...temperatures but eflloresces in dry and warm air. By heat, it first fuses, in its water of crystallisation, then at a red heat is decomposed into sulphurous acid, oxygen, and glucina. Water at 57-2 F. (l4 C.) dissolves about its own weight of this salt; its solubility is increased by heat, and boiling water dissolves an indefinite quantity. The presence of free sulphuric acid or alcohol lessens its solubility. It loses a portion of its acid in many cases with facility; for instance, we obtain an uncrystallisable tribasic sulphate of glucina, by dissolving carbonate of glucinain a concentrated solution of the sulphate; carbonate of glucina is added until carbonic acid ceases to be liberated at each addition; the liquid filtered and evaporated gives a gummy residue. The very dilute solution of this salt lets fall some glucina, and is changed into a bibasic sulphate, also uncrystallisable. Sulphate of glucinu dissolves zinc with disengagement of hydrogen, forming a bibasic sulphate of glucina and sulphate of zinc. Sulphate of alumina, under the same circumstances, dissolves zinc with liberation of hydrogen, and forms asulphate of zinc and an insoluble subsulphate of alumina. Taking advantage of this difference, Debray proposed a method (Ann. Ch/m. et Phys. xliv. 26), for the separation of alumina and gluciua, but which does not answer for analytical purposes, as chemically pure zinc is only acted on with great difficulty by these sulphates. Sulphate of glucina is formed by dissolving the carbonate in dilute sulphuric acid, the evaporated liquid depositing it on cooling. It is essential to keep the liquid distinctly acid; it assists the crystallisation, and besides, if we were to dissolve the carbonate in it until the liberation of carbonic...