306 Fluoric Acid in the Enamel of Human Teeth. 



other (namely, Uie major third). My allusion is to the 

 12th quints and the major thirds compared with the octave ; 

 that being the case, every attempt must be unavailing to 

 temper or assimilate two tones in direct opposition to each 

 other. I am therefore fully persuaded that the method I 

 have acted upon is good, being nearly the same in its effect 

 as that now in general practice ; and unless an instrument 

 can be furnished with two scales, one with sharps and an- 

 other with flats, there are very little hopes of ever melio- 

 ratmg common keved instruments : but I am of opinion 

 that such an instrument may be constructed without an ad- 

 ditional key; of which more hereafter. The temperament 

 would then be by flattening all the fifths of each scale to the 

 7th sharp and 7th flat; by which method the enharmonics, 

 or quarter-tones difference, will cease to be, and no other 

 substitutes but major and minor tones for each other will be 

 required ; for that tone which in one key is a major, will in 

 another be apposite for a minor tone, by the above mode of 

 temperament. 



I am, yours, &c. 



William Hawkes. 



XLTII. Qn the Discovery of the Fluoric Acid in the Enamel 

 of Human Teeth; on Tantalite and Yttro-tantalite ; on 



: Cerium; and on the Production of the Muriatic Acid 

 hj Means of Galvanism. Extracted from a Letter of 



M' BeRZELIUS to M. VAUaUELIN*. 

 Yl" Stockholm, Nov. 2, 180(5. 



il.wiNG been informed of the discovery of M. Morichini, 

 tv ho found fluoric acid in the enamel of teeth f, I made an 

 analysis of bones a little more in detail than any hitherto 

 attempted. I found that fresh bones contain, as well as the 

 enamel of teeth, fluate of lime, and that this fluate, by ab- 

 sorption from the bones, exists also in urine, dissolved with 

 phosphate of lime by means of free phosphoric acid. The 



• Annates dc Chimie, torn. Ixi. p. 256. 

 • t See Phil. Mag. voJ.xivii. p. 88. 



precipitate 



