ON "silver. 367 



the cause has not been well explained. All the theories Mineralogy of 

 on the subject arc lame and unsatisfactory. In the other Shetland. 

 Shetland isles which I have examined, the western coasts 

 SLte generally the most bold, and are composed of rocks 

 more indisputably belonging to that class called primitive^ 

 than those on their eastern shores. The same remark 

 may be extended to the sister isles of Orkney, and even 

 to Great Britain. 



Preston's chart of the Shetland islands, is the only 

 tolerable one we have : but it is inaccurate in the north- 

 ern part, which, I have been told, he did not live to sur- 

 rey. The southern parts of Shetland were laid down by 

 himself, and are extremely accurate ; but the northern 

 parts were carelessly added by some inferior hand at his 

 death, I have even seen a small island or rock that is 

 always uncovered, which is not in the chart at all. Mr. 

 Jameson's small map is pretty correct. It would cer- 

 tainly be worth the attention of Government to cause a 

 nautical survey of these islands to be made, with the 

 same minuteness and accuracy that the Orkneys are laid 

 down in the admirable charts of Murdoch Mackenzie. 

 Pinkerton, in his Geography, seems to have supposed, 

 that the Orkney coasts are as ill laid down as those of 

 Shetland. He says, " We have better charts of the 

 '' coasts of New Holland than of the Isles of Orkney 

 f and Shetland." Strange, that he should be unac- 

 quainted with Mackenzie's Charts^ which every vessel that 

 ^ails the North Sea invariably carries ! 



^ V. , 



facts toward forming a History of Silver. Bt/ Profsssor 

 Proust*. 



_ HK muriat of silver is soluble in muriatic acid ; it Muriat of sil. 



iseparates^ from it in octahedral crystals. This solution "^^^ soluble im, 

 ' . xaunatic agid. 



* Translated from the " Journal de Phyiiquc," Maxch 1806, 

 |). air. 



D»d 2 i« 



