﻿316 Transactions — Cliemistry. 



forming any opinion based upon those visible pliysictil changes which are the 

 iisiial concomitants of chemical action. Thus I am compelled to attack the 

 subject by indirect methods, and these, being individually less decisive for the 

 object in view, require a certain amount of variation to make up for their 

 want of directness. 



Judging from a variety of circumstances, which I need not here detail, I 

 am inclined to believe a sub-sulphide of gold or platinum is pi'oduced in these 

 experiments, and that in the case of the gold sulphide its colour is yellow, 

 which, if tru.e, would well account for the fact that no visible change is 

 induced upon this metal by sulphurization. 



It is very probable that were a bundle of light rays reflected from a series 

 of gold plates in succession, and another from a series of sulphurized gold 

 plates, a very manifest difference in the colour of the rays so reflected would 

 be apparent. 



It is only proper to state here that Professor Becquerel has just announced, 

 in a series of papers, a certain electro-motive power of gold, platinum, etc., in 

 pure water and also in neutral saline solutions, abstracts of which are given in 

 the several numbers of the " Chemical News," which I have placed upon the 

 table for the reference of members. This is exceedingly relative to the subject 

 of this paper, but it will be observed on reading these abstracts that the results 

 of the author's researches are quite distinct from those here described, since 

 the electric phenomena which he describes "are very feeble," while those I have 

 cited were sti"ong enough to decompose metallic solutions. Moreover, these 

 currents were produced by Professor Becquerel under such circumstances that 

 he was driven to the conclusion " that capillary affinity plays a very important 

 part in their production ;" whereas the currents which I have described are so 

 far superior to those producible by the exercise of capillary afiiuity that the 

 influence of such affinities upon them would not be perceptible by aid of the 

 instruments used. The sulphides do not appear, however, to have been experi- 

 mented with by Professor Becquerel in the researches I have alluded to. 



Art. LIII. — Preliminary Notes on the Isolation of the Bitter Substance of the 

 Nut of the Karaka Tree (Corynocarpus laevigata). By W. Skey, Analyst 

 to the Geological Survey of New Zealand. 



[Read before the Wellington Philosophical Society, 1st July, 1871.] 



A. VERY interesting as well as a most important investigation in any country, 

 whether for toxological or for scientific purposes generally, is that which has 

 for its object the identification and examination of the particular principle to 



