', 



ANALYSIS OF LlTIIOMARGE. 173 



If expofed in powder to the fire raifcd gradu- 

 ally to a white heat, it emits aqueous vapours, 

 and an cmpyreumatic odour. The papers of re- 

 action indicate the prcfence of an acid. Juil 

 before igniiion the mafs' becomes of a black co- 

 lour, but afterwards this colour difappcars. 

 When cooled, the centenary is found to have 

 loft I 3 pounds. 



A fmall piece placed on a coal, and receiving 

 the ilame of the blow-pipe, decrepitates, turns 

 black, and melts with ebullition, leaving a white 

 frothy Hug. With the microcofmic fait, it ex- 

 hibits the fame phrenomena as the Lcinniau 

 earth ; but a grain of it thrown into a folution 

 ofth'j fait becomes white. It cficrvcfccs lefs 

 with the fait of foda. 



We purfued the fame method of analyfis as 

 \vith the Lcmnian earth. From the fmall ex- 

 periments, indeed, a trillling quantity only of 

 jra^nelia was difcovered; but, that itr, pro- 

 portion might be more accurately afccrtained, 

 we examined half of the folution with the pow- 

 der of chalk, and the refill t was not more than 

 a quarter of a pound of magnelia. 



Collecting all thcfe circumftanccs then toge- 

 ther, it appears, that a centenary ofOfmundic 

 earth contains about 60 parts of white filiccous 

 powder, 5.7 of calcareous earth, 0.5 of magne- 

 lia, i J.I of argillaceous earth, 4.7 of calcined 

 iron, and i3 of a nioiil volatile matter. 



The 



