266 Experiments upon new Ivory, fossil Ivory, 



The differences which exist among the losses experienced 

 by the different ivories in calcination may be explained by 

 the state in which they are found : the fossil ivory of Siberia 

 and of Loyo were almost entirely in their natural state ; they 

 preserved the greatest part of their animal gluten and their 

 organization, while those of the canal of Lourque, of Peru, 

 and of Argenteuil, had lost this matter and had become dry. 

 The latter, also, easily split into scales, were extremely brittle, 

 and sent forth only a very slight animal smell during cal- 

 cination : as to the enamel of teeth, the small loss which it 

 sustains by the same operation, announces that ic contains 

 much less humidity or animal mucilage than other bones, 

 as was before well known: the latter assumed a bright blue 

 colour upon being exposed to heat, which proves that it con- 

 tains a notable quantity of phosphate of lime. 



After having been calcined and pulverized, each of these 

 matters was treated in the following manner, to know if we 

 could ascertain the presence of the fluoric acid. Portions 

 of the calcined ivories were placed in a common phial, and 

 also in a small retort : four parts of concentrated sulphuric 

 acid were poured upon the ivory; to these vessels was adapted 

 a glass tube which was inserted in lime water, and they were 

 then heated. In each of these experiments no more than 

 twenty grammes were employed at a time, and never less 

 than five. 



Neither fresh ivory nor the enamel of teeth gave any traces 

 whatever of the fluoric acid : the fossil ivories of Siberia and 

 of Loyo were alike destitute of it ; but those of the canal of 

 Lourque, and Argenteuil, gave evident signs of this acid. 

 In the latter cases, the upper part of the phials and retorts, 

 as well as the tubes made use of, were covered with a white 

 powder, the properties of which resembled silex ; in the 

 other cases nothing similar appeared. 



These first resi.lts having inclined us to doubt the exist- 

 ence of the fluoric acid in new ivory, as well as in such 

 ivory (although fossil) which still retained almost entirely, 

 and without alteration, the animal matter, we made artifi- 

 cial mixtures, with fresh ivory and fluate of lime, in the se- 

 veral proportions of a 25th and a 40th part; and always, 



even. 



