64 KEPOHT 1870. 



On the Phi/siologiml Action of Pyro-, Meta-, and Ortho -phosphoric Acids. 



By Prof. Gamgee, F.B.S. 



On the Influence of the Condition and Quantity of the Negative Element on the 

 Action of the Copper-Zinc Couple. By Professor Gladstone, F.B.S. 



On Solid Water. By Prof. Gutheie, F.B.S. 



On the Critical Point of Liquid Carbonic Acid in Minerals. 

 ByW. JST. Hartley. 



The History of Copper-extraction by the Wet Way. 

 By William Hendeeson. 



In this paper the author related the history of the introduction of these processes 

 and their establishment in this country and abroad ; he described the various stages 

 of the manufacture of Spanish cupreous pyrites by his processes ; he also described 

 and illustrated by specimens the recent modifications introduced for improving the 

 quality of the copper, and at the same time separating the small quantity of lead, 

 eilver, and gold always present in Spanish pyrites. 



On the Purification of the Clyde. By Col. Hope, V.C. 



On the Limited Oxidation of Terpenes. — Part IV.* 

 By Charles T. Kingzett, F.C.S. 



In this part of his researches the author has more particularly inquired into 

 the phenomena attendant upon the atmospheric oxidation of turpentine in the pre- 

 sence of water.' These phenomena may be staled as: — 



(ff) Increase of the specific gravity of the oil as the oxidation proceeds. 



(h) Gradual increase in the amount of peroxide of hydrogen produced, or the rate 

 at which it forms. 



(c) Gradual heightening of the boiling-point of the oil as it oxidizes. 



The oxidation, which takes place slowly at first, proceeds very actively after- 

 wards, and the oil thus under treatment is capable of inducing fresh turpentine, 

 which may be added to undergo oxidation at the same rate from the moment of 

 contact. 



The oxidized oil evolves large quantities of oxygen on heating to near 160° C, 

 and this oxygen is doubtless derived from camphoric peroxide. To the same sub- 

 stance the author assumes to be due the camphoric acid and peroxide of hydrogen 

 found in the aqueous solution that results from its decomposition with water. 



There are contained also in the watery solution obtained when turpentine is 

 atmospherically oxidized in the presence of water, acetic acid, camphor, &c. Thus 

 a solution obtained in one experiment upon several gallons of tm-pentine contained 

 323 grains of peroxide of hydrogen and 3G7 grains of camphoric and acetic acids. 

 The amount of peroxide of hydrogen produced is simply limited by the amount of 

 turpentine oxidized, and can be regulated at will. 



This aqueous solution the author has proved to possess most powerful characters 

 as an antiseptic and disinfectant, and continued investigations have shown these 

 characters to be possessed by the individual constituents of the solution, viz. cam- 



* Printed in extenso in Ohem. News, vol. xxxiv. pp. 127 & 135, and in Pharm. Jouru. 

 Sept. 23, 1876. 



