84 3f . Rose's Analysis of the [Oct. 



this investigation, and we confidently predict that his keen and 

 indefatigable genius will ultimately triumph over eveiy present 

 obstacle. 



The two Admiralty Orders quoted above show the sense which 

 that Board entertains of the value of Sir Humphry Davy's disco- 

 very with respect to ships in ordinary ; and the intelligent 

 author of the article in the Devonport Telegraph has justly and 

 forcibly insisted on its immense importance in that point of view 

 alone. But in the opinion of the Plymouth Editor, Sir Hum- 

 phry Davy's plan is 2i failure. *' Thy wish was father, Harry, to 

 thy thought, though why it should be so, we know not ; that 

 is no business of ours : — so, without further comment, to his 

 wishes and his thoughts we leave him. — C. 



Article IX. 



Analysis of the Seleniurets of the Eastern Harz, 

 By M. Henry Rose.* 



The seleniferous minerals, whose analysis is subjoined, were 

 discovered by M. Zinken, mine-engineer to the Duke of 

 Anhalt-Bernburg. They are found in the eastern part of the 

 Harz, at two places, situated at a small distance from each other, 

 one of which is near Zorge, in the veins of iron which traverse 

 the argillaceous schist and diorite : these seleniurets are disse- 

 minated in magnesian carbonate of lime. The other point is 

 near Tibzerode, in the veins. The seleniurets at the latter place 

 are found in larger quantity, dispersed also in magnesian car- 

 bonate of lime, and are frequently accompanied by small quan- 

 tities of native gold. 



M. Zinken observed the presence of selenium in these mine- 

 rals in 1823. He had the goodness to send me a large quantity 

 of the seleniurets, of which I have analysed only five varieties, 

 the rest not being sufficiently pure to be calculated for a quanti- 

 tative analysis. 



I analysed these minerals by means of chlorine. I converted 

 all the metals they contain into chlorides, and separated the 

 chloride of selenium, which is volatile, from the rest which are 

 fixed. I did not use nitric acid, or aqua regia, to dissolve these 

 minerals, because they always contain lead, and consequently I 

 should have been obhged to precipitate the oxide of lead by 

 sulphuric acid ; but in order to obtain the whole of the sulphate 

 of lead, it would have been necessary to evaporate the liquid to 

 dryness, and to heat the dry mass, to drive ofFall the free acids ; 

 Ivhich would have rendered it impossible to determine the quan- 



* From the Annales de Chimic. 



