546 Chronicles of Science. [Oct., 



The quantities of the metals obtained from these ores were as 

 follows : — 



1865. 1866. 



Iron 



Tin. 



Copper 



Lead 



Zinc 



Silver from the lead 

 Gold 



Tons. 



Tons. 



4,819.254 



4,530.051 



10,039 

 11.888 

 67,181 



9,990 

 11,153 

 67,390 



4,040 



3.192 



Ozs. 



Ozs. 



724,856 

 1,664 



636,188 

 743 



The total value of the mineral productions of these islands in 

 1866 is given as follows : — 



Metals obtained from ores raised from the British mines . £14,954.695 

 Coals, estimated price at the place of production . . 25,407,635 

 Earthy minerals, not building stones 1,350,000 



£41,712,330 



This and the last year have presented a depression in mining 

 adventure which has not been equalled within the present centuiy. 

 All our mining interests have suffered to a greater or less degree, 

 but the Tin and the Copper Mines of Cornwall and Devonshire 

 have in almost every instance been worked at a ruinous loss. 

 The result of this has been the emigration of more than seven 

 thousand miners, the closing of a great number of mines, and 

 the reduction of the work in many more. We learn from the 

 'Mineral Statistics' that tin ore in 1859 was 74Z. 15s. per ton; 

 whereas, in 1866, it was only 487. 10s. 9cZ. The price of copper 

 ore has also fallen, it being, in 1859, 51. 19s. a ton, and in 1866, 

 4:1. lis. There has also been a very steady falling off in the pro- 

 duction of fine copper during that period. 



In connection with mining for the precious metals, a most 

 elaborate and eminently useful volume, ' The Mining and Metal- 

 lurgy of Gold and Silver ' in all parts of the world, has been 

 produced by Mr. John Arthur Phillips, who is already well known 

 by his 'Manual of Metallurgy.' We must content ourselves at 

 present with this passing notice of the appearance of this splendid 

 volume. Its importance is such that it demands from us a careful 

 examination at an early period. 



Several sets of experiments have been made on the different va- 

 rieties of Safety Lamps in use in this country and in Belgium. One 

 set was made some short time since at Newcastle, and more recently 

 another set of similar experiments have been carefully carried out 

 at Barnsley. The experiments in both cases consisted in exposing 

 the safety lamps under trial to regulated currents of explosive mix- 



