en certain Stony and Metalline Sub/lances. 333 



Examination of the Stone from Bohemia. 



The probability of never being able to obtain another fpe- 

 cimen of the very remarkable fragment of this fubdance, did 

 not allow me to trefpafs more on the liberality of Mr. Gre- 

 ville, than to detach a fmall portion. I found it of fimilar 

 compofition to that of the three preceding (tones ; and the 

 count de Bournon has already mown the proportionate 

 quantity of the attractable metal to be very confiderable. 

 16 £ grains left z\ of extraneous earthy matter; and yielded, 

 by the treatment with nitric acid and ammonia, tfi grains 

 of oxide of iron. This would feem to induce an edimation 

 of l[- of nickel in 14 grains, or about nine per cent. 



$5 grains of the earthy part of the (tone, by the analytical 

 treatment of the two former, afforded, 



Silica - - - - - 25 

 Magnefia - - - 9'- 



Oxideofiron - 23 ■£ 



Oxide of nickel - - f | 



The unufual increafe of weight in the refult of the three 

 laft analyfes, notwithstanding the entire lofs of the fulphur 

 in the pyrites, is obvioufly owing to the metallic date of the 

 iron combined with the fulphur, as was mown in a former 

 inftance. 



I have now concluded the chemical examination of thefe 

 four extraordinary fubfiances. It unfortunately differs from 

 the analylis made by the French academicians, of the done' 

 prefented to them by the abbe Bachelay, as well as from that 

 made by profeffor Barthold of the done of Enfifheim. It is 

 at variance with that of the academicians, inafmuch as they 

 found neither magnefla nor nickel. It differs from that of 

 Mr. Barthold, as he did not find nickel, hut discovered fome 

 lime, with 17 per cent, of alumina. With regard to thefe 

 differences, I have to fubmit to the chemical world, whether 

 magnefla might not have eluded the action of an acid, when 

 the aggregation of the integrant parts of the done was not 

 dedroved by treatment with potafh. As to the exidence of 

 alumina, I do not absolutely deny it ; yet I mud obferve, 

 that the whole of the earth which feemed to have any re- 

 femblam ■•_•, however fmall, to alumina, was at mod 3 per 

 cent., and there feems good reafon to confider it as lilica. 

 Reflecting the exiltc ce of lime in the done of Enfifheim, I 

 mult appeal to profeflbr Barthold, whether, fuppofing lime a 

 comiituem part, fuiuhateof lime ihorrld not have been formed, 



as 



