306 Chronicles of Science. [April, 



following, drawn from the occurrence of a felspar with a small pro- 

 portion of silica in crystalline rocks containing free quartz : — 



" As this felspar occurs in rocks which contain uncombined silica in 

 the form of quartz, as well as in those that do not, and as the ratio of its 

 soda and lime, alumina, and silica, is as 1 : 1 : 3, nearly, we are justified, I 

 think, in concluding that it could never have co-existed in a completely 

 melted condition along with free silica, also in a state of fusion, or it would 

 have entered into combination with the latter to form a felspar, like albite 

 or orthoclase, in which the ratio is as 1 : 1 : 4 ; and we have thus confir- 

 matory evidence that these rocks are not eruptive." 



The Council of the Geological Society have this year awarded the 

 Wollaston Gold Medal to Thomas Davidson, Esq., F.R.S., F.G.S., &c, 

 for the highly important services he has rendered through many years 

 to the science of Geology, by his critical and philosophical works on 

 ' Fossil Brachiopoda;' and the Balance of the Proceeds of the Wol- 

 laston Donation-fund to J. W. Salter, Esq., F.G.S., &c, in recognition 

 of his valuable services in the elucidation of Palaeozoic Fossils, and 

 to assist him in completing his Monograph of British Trilobites. 



VIII. MINING, MINERALOGY, AND METALLURGY. 



Mining. 



It is seldom that Mining has been in so very unsatisfactory a state in 

 this country as it is at present. From the large accumulation of 

 stocks, the price of tin remains exceedingly low, and there are not 

 half-a-dozen of the tin mines of Cornwall which are working with 

 any profit. If this state of things continues, a great many must cease 

 to work, and those which are kept in operation must be maintained at 

 a considerable loss. The condition of things may be judged of from 

 one or two statements lately made by the managers of important tin 

 mines. Captain Charles Thomas, of Dolcoath mine, says — " The 

 average price of tin credited to-day is 57Z. Is. the ton, or 5/. 9s. per 

 ton less than the preceding six months, making a difference of 950Z. 

 on the whole amount credited to-day." The purser of Providence 

 Mine remarks — " The average price of tin per ton received during the 

 quarter was 51. less than during the previous six months, or 121. 10s. 

 less than the average price for the last twelve years." 



At Great Work, the decline has stopped all dividends, which 

 would otherwise have been 121. per share quarterly. We consider 

 the present depression well worthy of record, since it will form a re- 

 markable chapter in the history of our mines. 



Our copper mines, too, are much depressed. The very large im- 

 portations of copper from South America, from Cuba, and from 

 Australia, interfere to a very serious extent with our own mines. 



In many districts, especially in Derbyshire and at Alston Moor, 

 the produce of our lead mines is falling off. 



We have not yet been able to ascertain the produce of coal in this 



