282 Mr David Forbes on Chemical Examination of 



100-00 100-00 



Klaproth has likewise analyzed two specimens of this 

 mineral, but gives also oxygen as a constituent. How- 

 ever, from the less perfect means of analysis employed by 

 him, and the circumstance that the results on adding make 

 up exactly the 100, it seems very doubtful as to there having 

 been any oxygen whatever in these specimens, and most 

 probable that the loss which occurred in analyzing them 

 had by him been regarded as oxygen, which has not been 

 found by any succeeding chemists. 



Whilst the results of Klaproth's analyses are therefore in- 

 troduced, I have likewise placed by their side the quantities 

 which would result after calculation on the supposition that 

 no oxygen was present, and that the deficiency thus pro- 

 duced was distributed equally over all the three consti- 

 tuents. 



100-0 10000 100-0 100-00 



From the analyses of this mineral which we have here 

 given, it will at once be seen that the results are so completely 

 at variance with one another, that it is impossible to bring 

 them under any distinct formula. There are also other ana- 

 lyses equally different, which, from fear of occupying too much 

 space, I have been obliged to leave out ; and although 

 Plattner has considered it probable that there are three dif- 

 ferent species included under this mineral, still it would re- 

 quire much more than double this number to reconcile all 

 the analyses which differ so essentially from one another. 



It must likewise be remembered, that if we adopt Piatt- 



