TRANSACTIONS OF THE SECTIONS. 43 



On Nitrite of Silver. By J. W. GATEnotrSE. 



The Relation of the Arranfjement of the Acids and Bases in a Mixture of Sails 

 to the original manner of Comhination. By Dr. J. H. GLiDsxoNE, F.R.8. 



The question proposed for cousideration was : — Suppose two salts (such as chloride 

 of sodium aud sulphate of magnesium) are mixed in equivalent proportions in a 

 certain quantity of water, is the solution identical with a mixture of equivalent 

 proportions of sulphate of sodium and chloride of mag-nesium in the same amount of 

 water ? The method emploj'ed for testing the question was to mix such pairs of 

 solutions with a certain quantity of an intensely coloiired salt, such as ferric sulpho- 

 cyanide, ferric meconate, terbromide of gold, or platino-iodide of potassium, and to 

 note the diminution of colour that resulted from the reciprocal decomposition of 

 the constituents. Four separate pairs of mixtures were examined, aud each pair 

 proved identical in its action on the coloured salts. As small differences can be 

 easily detected by such a method, the question may be considered as answered in 

 the afiirmative. 



Notes on tlie Action of the Copper-Zinc Couple*. 

 By Dr. J. H. Gladstone, F.Ii.S., and Alfred Tribe, 



Pure zinc will scarcely decompose a weak solution of sulphvu-ic acid ; but if a 

 minute quantity of copper be deposited on the same zinc, it will decompose it 

 readily. 



Zinc which contains arsenic when " coupled " with copper decomposes pure water 

 with the evolution of hydrogen which is free from arsenic. If, however, arsenious 

 acid be added to the solution, arseniuretted hydrogen makes its appearance. The 

 presence of this gas when arsenical zinc is dissolved in ^dphuric acid is most 

 probably due to the solubility of the arsenic in that acid. 



On the Avgmentation of the Chemical Activity of Aluminiiim by contact with 

 a more Negative Metal f. By Dr. J. H. Gladstone, F.B.S., and Alfred 

 Tribe. 



Aluminium alone decomposes water only at a white heat, but when " coupled " 

 with copper or platinum it will decompose water slowly at the ordinary temperature 

 aud rapidly at 100° 0. The aluminium-platinum couple, as might be expected, 

 gives a still larger amount of hydrogen in the same time. 



On an Apparatus for estimating Carbon Bisulphide in Coal-gas. 

 By A. Vernon Harcourt, F.B.S. 



On Derivates of Mercaptan. By L. Jackson and A. Oi-I^nheim. 



On the Oxidation of the Essential Oils. — The Limited Oxidation of Terpemeg 

 and CymeneX. By Charles T. Kingzett, F.C.S. ^x. 



This research is a continuation of work the results of which 1 liave commiiBicated: 

 to the Chemical Society (.Touru. Chem. Soc. ser. 2, vol. xii. p. oil, & vol. xiii. p. 210). 



In this Part the limited oxidation ("by air) of tei-penes of the general formula 

 C|„H,g and certain bodies related to terpenes, of the formula CijHji, antl cymeiie 

 (C,oII,,) is dealt with. 



AH terpenes represented by the expression C^ Hjs (so far as I have ir ivestigated) 



* Published in exienso in 'Phil. Mag.' October 1875, t* Ihid. 



I Vide ' Chemical News,' vol. xsxii. p. 138. 



4* 



