partment of analysis: but the process adopted by Mr, Talbot is more allied to that followed by Fagnani than by Abel, and is equally remarkable for its great simplicity and for the vast number of novel and interesting results which it furnishes, including not merely several of the most remarkable of those which are already known, but likewise many others which are apparently not deducible by other methods.
The Council have awarded the Royal Medal for Chemistry to Professor Thomas Graham for his paper entitled "Inquiries respecting the Constitution of Salts; of Oxalates, Nitrates, Phosphates, Sulphates, and Chlorides," which was read to the Society on the 24th of November 1836, and since published in the Philosophical Trans- actions. This paper they have considered as being the last of a series on a general subject of great importance: and as the sequel of Professor Graham's researches on the Arseniates, Phosphates, and modifications of Phosphoric Acid, read to the Society on the 19th of June 1833, and published in the Philosophical Transactions of the same year. He has therein shown that, by considering the water which enters into the composition of the different classes of salts, which the phosphoric acid forms with the several bases, and which has been considered as water of crystallization as standing in a basic relation to the acid, a very simple view might be taken of this very complicated subject. According to this theory, there are three sets of phosphates, in which the oxygen of the acid being 5, the oxygen in the base is respectively 3, 2, or 1 ; the remaining equivalents of oxygen, in the two first cases, being supplied by that portion which exists in the 2 or 3 equivalents, respectively, of the basic water, which water is wholly absent in the third case. These three classes of salts Professor Graham proposes to term, respectively, monobasic, bibasic, and tribasic salts. Professor Graham has extended these views of the basic formation of water in salts to the case of the sulphates, in a paper communicated to the Royal Society of Edinburgh, and published in the 13th volume of their Transactions, on "Water as a constituent of Salts." The principal object of this paper, however, was to show that water exists in a different state in certain salts, and does not exercise a true basic function, being capable of being replaced by a salt, and not by an alkaline base, and giving rise to a class of double salts. This inquiry was suggested by the tendency of phosphate of soda to unite with an additional dose of soda, and form a subsalt, which. had been traced to the existence of basic water in the former. The result was, that in the well-known class of sulphates, consisting of sulphates of magnesia, zinc, iron, manganese, copper, nickel and cobalt, all of which crystallize with either five or seven equivalents of water, one equivalent proved to be much more strongly united to the salt than the other four or six. The latter, to which the name of water of crystallization should be restricted, may generally be expelled by a heat under the boiling point of water; while the remaining equivalent uniformly requires a heat above 400° of Fahrenheit for its expul-
