W. Skey. — On the NudeaT Action of Gold. 373 



undissolved. Accidentally some extraneous substance, supposed to have been 

 a piece of cork, had fallen into the solution, decomposing it and causing the 

 gold to precipitate, which deposited in the metallic state, as in the electro- 

 plating process, around the small piece of undissolved gold, increasing it in 

 size to two or three times its original dimensions." 



The results alleged to have been obtained by Mr. Daintree appearing to 

 have, and indeed being recognized as having, a very important bearing upon 

 the popular question as to how our gold nuggets have been formed I have 

 endeavoured to obtain further details, but in this I have been unsuccessful. 

 Mr. Brough Smyth, indeed, in his work upon the Gold Fields and Mineral 

 Districts of Victoria, refers to what appears to be the same experiment, but 

 nothing further is there stated except that the size of the gold fragment 

 started with is increased from a "speck" to a "piece." I have therefore 

 tried to reproduce the results themselves, and having been unsuccessful I will 

 describe minutely the several modes I adopted. 



1st. -1315 grammes of gold, hammered thin and bent to a curved disc of 

 such a size as to expose about half a square inch of superficies, was placed in a 

 glass vessel containing two ounces of a solution of auric-chloride of a strength 

 equal to half a grain of gold per ounce. For reducing agents small pieces of 

 cork and wood were sunk by glass attachments to the bottom of the vessel in 

 close proximity to the disc of gold. 



The vessel was then closed, put in a darkened place, and suffered to 

 remain at rest until all the gold present in solution had been reduced, a 

 process occupying in this case a period of time equal to rather more than two 

 months. 



The gold disc was then carefully examined and weighed. It had a small 

 quantity of very finely granular gold loosely adherent to it, and apparently 

 equally disposed over its surface. 



With the whole of this loose gold attached the disc only increased in 

 weight -0005 of a gramme, or ^^ of its weight (a rate of increase that would 

 require about forty-four years to double the size of the disc), consequently only 

 about' the ~ part of the total amount of gold present in solution had deposited 

 upon the disc, the remainder having deposited away from it, and this was 

 seen to have indiscriminately attached itself to every surface which had 

 contact with the auriferous solution, whether the bottom or sides of the vessel, 

 the glass attachments, or even the surface of the liquid having contact only 

 with the atmosphere. 



In reference to the minute quantity deposited upon the gold disc it was 

 found by numerical calculation that the proportion was certainly not more, 

 relatively to the surface of the disc, than that which the remainder of the 

 gold bore to the extent of the surfaces upon which it had afiixed itself. 



