Experiments upon new Ivory, fossil Ivory, &c. 265 



attaches the shafts B to the body of the waggon, is then to 

 be removed, and with the shafts to be placed in a similar 

 manner at M on the other end of the waggon, which now 

 becomes the fore part, the horse drawing it back to be again 

 loaded. Whenever the waggon is ascending, the checks 

 behind the waggon may occasionally be let down and used 

 as rests to relieve the horse when necessary. 



XLIIT. Experiments made upon new Ivory, fossil Ivory, and 

 the Enamel of Teeth, in order to ascertain if these Sub- 

 stances contained Fluoric Acid. By Messrs. Fourcroy - 

 and VAuaoELiN. Read in the French Institute*. 



_Dy a letter inserted in No. 165 of the Annales de Chimie f 

 (see Philosophical Magazine, vol. xxiii. p. 264.) M. Gay 

 Lussac, the pupil and friend of M. Berthollet, announces 

 that Mr. Morichini, a chemist at Rome, had discovered the 

 presence of the fluoric acid in new ivory, fossil ivory, and 

 the enamel of teeth ; he found that new ivory was almost 

 cntirelv formed of filiate of lime, and that the enamel of teeth 

 contained nearly 22 per cent, of filiate of lime. 



This discovery is so interesting, that it becomes every man 

 of science to ascertain the truth of it. We shall give in this 

 paper the result of the experiments made by us upon the 

 subject in the laboratory of the Museum of Natural History. 

 As it would have been difficult, and perhaps impossible, 

 to make the sulphuric acid act conveniently upon these sub- 

 stances, if they had not been first cleared of their animal 

 gluten, we began by calcining them in an open crucible. 

 1st, New ivory lost by this calcination - 45 per cent. 

 2d, Fossil ivory of Siberia - - 41 £ 



3d, Fossil ivory of Loyo - - 41 



4th, Fossil ivory of Lourque - - 18 



5th, Fossil ivory of Peru, found at 1 1 76 feet 



above the level of the sea - - 1 5 



fith, Fossil ivory of Argenteuil - 11 



7 th, Enamel of teeth - - ll-j. 



* From Ar;\ales de Chimie, torn. !vi. p. 37. 



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The 



