a Specimen of Native Iron from South Africa. 33 



and apparently little liable to oxidation, qualities which are 

 observed in iron, of what is usually considered undoubted 

 meteoric origin. 



I should not think it necessary to detail the steps of the 

 analysis by which the presence ot" nickel in the proportion of 

 ^'6\ per cent, was demonstrated, but for a peculiarity in one 

 part of the process by which an inconvenience of frequent 

 occurrence in chemical operations, and of a very embarrassing 

 nature, was obviated, and which may prove useful as a hint to 

 young analysts in other cases. 



18'67 grains of the iron in one piece were digested in 

 dilute nitric acid, which dissolved the whole, with the excep- 

 tion of a trifling quantity of black scaly matter, apparently 

 amounting to about a quarter of a grain*. Towards the end 

 of the solution the iron more than once brightened on the 

 surface, and assumed that peculiar and singular state of re- 

 sistance to the action of the acid which I have described in 

 the Annales de Chimie for September 1833, and which has 

 since been the subject of so much interesting discussion by 

 Professor Schcenbein, Mr. Faraday, and others f- In con- 

 sequence, it was necessary to apply and maintain heat to 

 complete the solution. 



The nitric solution was evaporated to dryness, water 

 added, and evaporated a second and a third time. By this 

 the whole of the iron was peroxidized, and nearly the whole 

 separated. It was then diffused and boiled in water, to which 

 a few ilrops of nitric acid were added, to take up any oxide 

 of nickel which might have been deprived of its acid by over- 

 heating, and set aside for subsidence, filtration being out of 

 the question. 



After standing a week, however, it was still perfectlj^ 

 opake, and loaded with suspended peroxide of iron, and to 

 get rid of this was the next object. 



Lead being a metal easily eliminated, and incapable of 

 interfering in any of the subsequent processes, its introduc- 

 tion seemed not likely to prove any source of further em- 

 barrassment ; a few drops of dilute nitrate of lead were there- 

 fore added ; and being well mixed, as much sulphuric acid as 

 would satuiate the lead, and a little more, was added, and the 

 whole boiled. The precijiitation was complete, the lead car- 

 rying down with it all the suspended ferruginous matter, and 

 leaving a clear li(|uid of a greenish hue, in which the presence 

 of lead could not be detectetl. 



* This black scaly matter was in all probability 5r«/)/«7c, — Edit. 

 f See L. and E. Phil. Mag. vol. xi. p. JJSU.— Eurr. 



VhiL Mais. S. 3. Vol. H. No. 85. Ja7i. 1839. D 



