642 Original Articles. [Oct., 



deposits of tin are now worked at depths of between 200 fathoms and 

 300 fathoms from the surface. The result of sinking on the quartz 

 lodes in the mountains of Merionethshire will be watched with much 

 interest. 



Invariably when a good mine is discovered, a great many other 

 mines are started in the neighbourhood. This applies to every 

 variety of mine exploration, and is especially applicable to gold- 

 mining. Numerous attempts and failures have hitherto marked the 

 progress of mine-adventure in North Wales ; and it is generally 

 believed that more gold has been expended on the Welsh hills than 

 has been obtained from them. The authority whom we have already 

 quoted, speaking of the poorer varieties of quartz, says : — " The 

 Clogau Company has stamped 2,500 tons of poor ores, yielding an 

 average of 12 dwts. per ton ; and during the last two months the 

 Castele Cam Dochan Company has stamped 200 tons of the mineral 

 broken indiscriminately from their lode, with an average of 15 dwts. 

 of gold per ton. With good reduction machinery several of the gold 

 mines in the Dogelly district might yet be made to pay." It will be 

 most satisfactory to find the hopes thus expressed by Mr. Dean fully 

 realized. It is right that some idea should be given of the occasional 

 richness of this auriferous quartz. Mr. T. A. Eeadwin informs us* that 

 by far the richest discoveries of gold have been made at the Dol-y- 

 frwynog, Prince of Wales, and the Clogau Mines. He has, he states, 

 extracted gold from stones, from each of those mines, at the rate of 300 

 to 400 ounces to the ton. At the same time as he draws attention to the 

 exceeding richness of some specimens of the auriferous quartz, Mr. 

 Eeadwin says, with much honesty, " I beg distinctly to state that the 

 average yield will not, in my opinion, exceed half-an-ounce to the ton 

 of ore." 



Our readers will be familiar with the amalgamating process, by 

 which gold is separated from the earthy minerals with which it is 

 mixed. The extraction of gold by amalgamation is, however, 

 attended with serious difficulties. Whenever Sulphides, Arsenic, 

 Bismuth, or Tellurium are present with the gold, they frequently 

 tarnish the metal, and the mercury cannot act upon it. Technical 

 language informs us, that the mercury " sickens," that is, it grows 

 thick, or that it " flours," meaning that it becomes pulverulent. 

 These conditions are dependent upon the presence of other metals. 

 Under either of those circumstances much of the gold escapes the 

 influence of the mercury and is lost in the " tailings," whilst much 

 of the mercury itself is carried off in the washings. Mr. William 

 Crookes, F.R.S., the discoverer of the new metal Thallium, has 

 introduced an improvement, which promises to be of the utmost 

 advantage, in all our operations for obtaining gold in quartz-mining, 

 or when it is combined with other minerals. 



Mr. Crookes's process possesses the following important advan- 

 tages : — By the judicious admixture of a certain proportion of 

 Sodium with the mercury its amalgamating powers are, under all 



* " On the recent Discovery of Gold in Merionethshire." By T. A. Eeadwin, 

 F.G.S. ' British Association Reports for 1863.' 



