218 GOLD IN SCIENCE AND IN INDUSTRY. 



gold extraction has spread over the gokl-producing countries of the 

 world, now absorbing and now replacing the older processes, but 

 ever carrying all before it — all this is already a twice-told tale which I 

 should feel hardly justified in alluding to were it not for the fact 

 that we are to-day meeting on the Rand where the infant process 

 made its debut nearly fourteen years ago. The Rand to-day is the 

 richest of the world's gold fields, not only in its present capacity, but 

 in its potentialities for the future ; twenty years ago its wonderful 

 possibilities were quite unsuspected even ])y experts. 



It is not for me to describe in detail how the change has been 

 accomplished; this task will, we know, be far better accomplished 

 by representative chemists who are now actively engaged in the work. 

 But for the chemists of the British Association it is a fact of great 

 significance that they ai"e here in the presence of the most truly in- 

 dustrial development of gold production which the world has yet 

 seen — a development moreover that is founded on a jjurely chemical 

 process which for its continuance requires not only skilled chemists 

 to superintend its operation, l)ut equally skilled chemists to supply 

 the reagent on which the industry depends. 



In 1880 the Avorld's consumption of cyanide of potassium did 

 not exceed 50 tons per annum. This was produced by melting 

 ferrocyanide with carbonate of potassium, the clear fused cyanide 

 so obtained being decanted from the carbide of iron which had 

 separated. The' resulting salt was a mixture of cyanide, cyanate, 

 and carbonate, which was sometimes called cyanide of potas- 

 sium for the hardly sufficient reason that it contained 30 per cent of 

 that salt. When the demand for gold extraction arose, it was at first 

 entirely met by this jorocess, the requisite ferrocyanide being ob- 

 tained by the old fusion process from the nitrogen of horns, leather, 

 etc. In 1891 the first successful process for the synthetic production 

 of cyanide without the intervention of ferrocyanide was perfected, 

 and the increasing demand from the gold mines was largely met by 

 its use. At present the entire consumption of cyanide is not much 

 short of 10,000 tons a year, of which the Transvaal gold field con- 

 sumes about one-third. Large cyanide works exist in Great Britain, 

 Germany, France, and America, so that a steady and sure supply of 

 the reagent has been amply provided. In 189'4 the price of cyanide 

 in the Transvaal was 2 shillings per pound ; to-day it is one-third of 

 that, or 8 pence. During the prevalence of the high prices, of earlier 

 years the manufacture was a highly speculative one, and new proc- 

 esses appeared and disappeared with surprising suddenness, the dis- 

 appearance being generally marked by the simultaneous vanishing 

 of large sums of money. To-day the manufacture is entirely carried 

 out in large works scientifically organized and supervised, and, both 



