Geographical Notices. 



excess of pure chlorid of ammonium and ignited in a clean 

 porcelain crucible, when pure metallic rhodium remains as a 

 porous mass mixed with chlorid of potassium. 



When the process above described has been carefully con- 

 ducted,_and especially when the quantity of nitrite of soda added 



nt, the 

 Thodii 



lium and ruthenium, and to be free from iridium. 

 If however, after converting the sulphids into double chlorids in 

 the manner pointed out, iridium is found to be present, the pro- 

 cess to be pursued is still the same so far as regards the separa- 

 tion of the ruthenium ; the remaining mass is then to be dissolved 

 in water with addition of chlorhvdric acid, the solution nearly 

 neutralized with ammonia, the platinum and rhodium separated 

 as sulphids in the manner already pointed out, brought into the 

 form of double chlorids and then separated by nitrite of potash 

 as before. 



For the complete success of this method it is absolutely neces- 

 sary that the mass of mixed double chlorids be freed from osmi- 

 um as completely as possible. This is to be done in the usual 

 manner by repeated evaporation with nitro-muriatic acid. 



In place of the method above given the following may also 

 be employed with success and are sometimes more convenient. 



Art. XXXI.—GeogrcqjhKcd Xoiices. No. XVIII. 



RETURX OF hall's ARCTIC EXPEDITION. 



The latest, it is doubtful whether we can say the last, of the 

 Arctic explorers has safely returned to this country. We learn 

 that at an early day he is to present the results of his explora- 

 tions in a paper to be read before the American Geographical 

 Society, which will undoubtedly be printed. Meanwhile, we 

 owe the following sketch of his journey to one of his adviser^ 

 and friends, a public spirited gentleman in New London. 



It may be recollected that in the year 1860, Mr. C. F. Hall oi 

 Cincinnati, planned and started an expedition, on a plau some^ 

 what novel, for the purjt)se of exploring the regions north ana 

 west of Hudson's Straits, in British America, and to discover^ 

 possible further relics and remains of the lost and mourned an 

 John Franklin and his crews. .,i^ 



The peculiarity of Mr. Hall's efforts were that dispensing vrm 

 vessels, men, provisions, fuel, kc, he proposed a journey ove 

 the trackless snow-fields alone, or with companions found amoHn 

 the roving Esquimeaux, whose habits and mode of life he pr^ 



