458 Scientific Proceedings, Royal Dublin Society. 



Report it appears that an appreciable trace of gold was found 

 corresponding to about 469 milligrams to the ton of washed ash, 

 = 7, grains 22. Considering the enormous yearly production of 

 coal in Great Britain alone, which has reached 170 millions tons for 

 the year 1887, representing a proportion of ash which may be 

 taken at 5 °/ G or 8 -5 millions, taking the heavy part assayed in 

 this case as only the half of the total ash the quantity of gold con- 

 tained in the ash of a year's production would be about 2125 

 kilogrammes, value about £377,714. 



Here again there is occasion to remark that the assay may have 

 been made on an accidentally exceptional sample ; but there are 

 other considerations to be taken into account as well. If gold be 

 generally present in coal ashes, which will be assumed here, 

 evidently there should be a difference in the quantity contained, 

 according to the nature of the ash, and even to the physical condi- 

 tions of the coal-field ; moreover it may be that the most impure 

 varieties of coal, and those carrying the largest quantity of pyrites, 

 contain the largest amount of gold (since the quantity of precious 

 metal contained may be assumed to be proportional to the quantity 

 of ash). Hence the interest there is in having a series of compa- 

 rative assays of coal ash made with a view to ascertaining those 

 which may contain gold in notable quantity, and allow of an 

 attempt being made to turn to account the ashes which, as a by 

 product, may be taken as of extremely low value in their actual state. 



In conclusion it may not be out of place to point out that 

 research is very active at present with a view to discovering better 

 and cheaper methods of extraction of gold from the matrix, and 

 of saving the metal already free and liable to escape with the fine 

 slimes and thus be lost. In this respect Lock's remarks are of im- 

 portance (I. c. Introduction, p. v.) " In the more difficult operations 

 of extracting gold from mineral veins and complex ores, reliable 

 evidence from all parts of the world shows that most of the pro- 

 cesses at present in use or the methods of carrying them out, are 

 far from satisfactoiy, as they entail the loss on the average, of 5 

 to ^ of the gold present in the material operated on." 



These facts point unmistakably to the necessity of studying 

 the conditions under which gold occurs.. 



As one of the latest examples of this activity may be cited the 

 report of the meeting of " The Economic Gold Extraction Co.," from 



