Pluoric Acid hi the Enamel of Human Teeth. 307 



precipitate obtained from urine by means of lime water, 

 when washed and dried, gives with sulphuric acid fluoric acid 

 gas, which corrodes glass. But there must be a considera- 

 ble quantity of this precipitate, in order to have very sen- 

 sible marks of it. On decomposing, by the acetate of lead, 

 burnt human bones dissolved in nitric acid, I found mag- 

 nesia in them, although in a smaller quantity than in the 

 bones of herbivorous animals. 



The following is the result of my labours : 



Cartilage 

 Blood-vessels 

 Fluate of lime 

 Phosphate of lime - 

 Carbonate of lime - 

 Phosphate of magesia 

 Soda, muriate of soda, 

 water, Sec. 



1 20 



100 



2-0 



100 



-45 



100 



1-34 



100 



Human teeth contain the same earthy substances as enamel 

 does ; but they contain cartilage also. The Analysis of Urine 

 above alluded to, was printed at the beginning of the year in a 

 kind of Journal of Chemistry, edited by Kisinger and. myself, 

 under the title of yifhandUngari Jysik, Kcmi af Miner alogi, 

 of which we should have had the honour of transmitting a 

 copy, if the war had not interrupted ail communication. 



M. Gahn has found tantalite and yttro-tantalite at Tahlun. 

 By his address in managing the blowpipe he discovered that 

 the tantalum of M. Eckeberg is only tin combined with an 

 earth which he has not yet ascertained. M. Eckeberg is a^ 

 present occupied with a more detailed examination of this 

 combination. v 



The Upsal chemists at first thought that cerium was only 



a mixture of barytes, yttria, and magnesia ; M. Eckeberg, 



tkishing to compare them, found that yttria, when a long 



time exposed to the fire, gives also oxymuriatic acid by di^- 



U 2 solviwjp 



