On Grauelltj and Calculous Concretions. IQQ 



For mc, therefore, to return to the process already pointed 

 out, A, which consists in a partial decomposition of nitrate 

 of ammoniacal nickel : for that which has been proposed 

 by Lehman, to melt the nickel mixed with cobalt from fif- 

 teen to twenty times, to a commencement of vitrification, 

 for the purpose of scorifying all the cobalt; as well as tha^.- 

 pointed out by Bergman, to repeat the melting three or 

 four times with eight or twelve times as much or pure ni- 

 tre, was too troublesome and expensive. In consequence, 

 I repeatedly treated the oxide of nickel, which by means of 

 carbonate of potash had been separated from the triple salt 

 not dissolved by the former evaporation, in such a manner 

 that, after having dissolved it by nitric acid, I had rccotifse 

 to ammonia and to evaporation, as explained above. 



It is thus that I finally obtained, entirely exempt from co- 

 balt, the oxide separated by potash from the triple salt whii;h 

 had been rcdissolved after evaporation. 



The oxide which was separated by the evaporation cf 

 the nitrate of ammoniacal nickel was in the former opera- 

 tion already entirely purged of cobalt; only it still contained, 

 as has been observed, a little nitric acid. Oxide of nickel, 

 which, after having been reduced to a state of nakedness by 

 evaporation, contains still some cobalt, is naturally sus- 

 ceptible of undcrgoine anew the same operation. 



By this method we may be served with the article in 

 question, until our further discoveries have showa lis one 

 more expeditious. It does not occasion any considerable 

 Expense ; for by means of potash we may efl'ect, in a retort, 

 the evaporation of nitrate of ammoniacal nickel, the same 

 as the subsequent decomposition of the triple salt, and thus 

 save the ammonia for other uses. As is the case in work* 

 on a great scale, we can also save a part of the nitrate from 

 the former operation by the evaporation of the water used 

 In washing it. 



XL. j4n cxperhncntcil Inqu'inj into the Kaltire of Gravel/i/ 

 and Calculous Concretions in the Human Suiject ; and tlie 

 Effects of Alkaline and Acid Substances on them, in and 

 out of the Body. By Thomas Egan, M.D. M.R.I.A.* 



JL HK constant occurrence of these afflicting complaints in 

 Simpson's (iouty Hospital, to which I have been phvsician 

 lor several years, first turned my serious attention to the 



* Itoiu Transutions of tht Ho^al Iriih .Indcmy. 



N 4 most 



