18 ANALYSIS. OF 



ame„ Fut into dilute nitric acid^a very flight efFervefcence was pro- 

 , which was momentary, when the flone was in powder; in a few 

 hours the whole of the flone .was diffolved with the exception of a ve- 

 ry minute portion of carbonaceous matter. This folution on the addi- 

 tion of ammonia afforded a copious precipitate, which was infoluble 

 in weak oxalic aci^. The precipitate being feparated by filtration, the 

 was rendered turbid by the iaft mentioned acid^ 



Results which prove that thefe ftones are compofed of phofpbate 

 df lime, with a little carbonate of lime and flight traces of carbon. Thus 

 their compoiltion is the fame as that of bone partially calcined, which 

 I have no doubt, they are in reality: their phyfical properties are thofe 

 of calcined bone as well as their cherriical nature; calcined bone fske 

 the Hones admits of being polifhed, affords when breathed on an earthy 

 fmell, adheres to moid fuj'faces and in f-diSL has every real property 

 ■ wliicli thefe ftones poircfs. 



Another kind of fnaie-ftone, of which I faw only a fingle fpeci- 

 men, was a fmall oval body fmooth and fhininr^, externally black, 

 internally grey; it had no earthy fmell when breathed on, and had no 

 abforbent or adheiive power* By the perfon who prefented it to Sir 

 Alexander Johnstone, it was, much valued and for adequate reafon, 

 if true, **' it had faved the lives of four men at leaft." 



Before the blow pipe it emitted a flight fmell like that of vegetable 

 matter burning and became white. In dilute nitric acid it diffolved 

 and effervefced ftrongly, and until the whole was diffolved the effer- 

 vefcence continued. The lolution was not precipitated by ammonia, 

 b'lt copiouily by carbonate of ammonia. The precipitate before ths 

 |)Jow-pipe was converted into pure quick lime^ 



