340 The PhUosophical Society of Glasgow. 



and latest authorities on the subject — bringing the information, in a 

 tabular form, down to 1857. 



The quantity of copper ore raised in Cornwall and Devon, and chiefly 

 sold by public ticketings, during 126 years, ending 1855, was 7,884,305 

 tons, which realized £50,964,388 sterling. The mean price per ton 

 of the whole was £6 9s. 3d., and the average yield for seventy years was 

 8 per cent, of fine copper. The return for ten years ending 1855 was 

 twenty-five times greater than from 1726 to 1735. The average pro- 

 duce for ten years ending 1785 was 12 per cent., and for a correspond- 

 ing period to the end of 1855, it had declined to 7|- per cent. ; for 1857 

 it was about 6f per cent. These figures clearly show the economic 

 value of the improvements effected in working mines. 



The average produce of the common ore of Cornwall has been esti- 

 mated at 2 per cent ; consequently, this calculation, applied to the num- 

 ber of tons sold during 126 years, will bring the quantity produced no 

 less than 31,537,220 tons. 



These ores are sold by a process called ticketing, and is thus ar- 

 ranged : — The ore is thrown into a heap, and three average samples are 

 taken. One of these is assayed on the part of the mine, another for 

 the smelters, whilst the third is retained in case of dispute. The sales 

 or ticketings take place at Redruth, Truro, and Poole, where the agents 

 offer for the small samples to be disposed of. When all have delivered 

 their offers or tickets the results are published in a tabular form. In 

 this hst a red hne distinguishes the highest bidder, who becomes the 

 purchaser. 



In a commercial point of view the copper mines of ChiH, Cuba, Spain, 

 and Australia are, after those of England, by far the most important, 

 and send large quantities to be smelted. For instance, there was im- 

 ported into England from the different foreign mines in 1857, 75,832 

 tons of ore and 19,262 tons of regulus. Tour or five years previous to 

 the discovery of the Australian gold fields, the increase of copper ore 

 was very definite. The produce of the Burra Burra mine, which in 

 1846 was 6,359 J tons ore, increased in 1850 to 18,692 tons. Since 

 then, by the abstraction of the miners to the gold fields and other cir- 

 cumstances, the product has been reduced in 1857 to 4,182 tons. 

 Foreign copper imported into this country and the product of the 

 foreign ores by smelting, were, previously to 1842, almost wholly re- 

 exported. The duty on copper ore, when taken or smelted for home use, 

 being so heavy as to cause it to be exported in an unwrought state. 



For 1842 the duty was much reduced, and in 1853 repealed, hence 

 the great increase in the imports of ore for smelting, and the applica- 

 tion of the metallic copper to home use or exportation indifferently. 



