475 



By a suitable course of experiment, the proportions of the several 



salts present were found to be nearly thus : 



Sulphate of potash 71 



Sulphate of soda 19 



Muriate of soda 5 



the remainder consisting of a little muriate of ammonia, mixed with 



the muriates of iron and copper. 



In the part which remained undissolved by water, there was also 



found to be submuriate of copper, similar in composition to the green 



sand of Peru, and a yellow powder that was judged to be submuriate 



of iron ; so that, on the whole, this single mass presented as many 



as nine different species of matter. 



Some Experiments and Observations on the Substances produced in dif- 

 ferent chemical Processes on Fluor Spar. By Sir Humphry Davy, 

 LL.D. F.R.S. V.P.R.I. Read July 8, 1813. [Phil. Trans. 1813, 

 p. 263.] 



In the Bakerian lecture for 1808, the author had supposed fluor 

 acid to be decomposed when potassium is heated in silicated fluoric 

 acid gas, and that oxygen was separated from it ; an inference which 

 had also been drawn from a similar experiment by Messrs. Gay- 

 Lussac and Thenard. But when he afterwards found that oxy muriatic 

 acid could not be decomposed, and that no oxygen could be separated 

 from the compounds of this body with phosphorus, sulphur, or the 

 metals, he was led to conceive an analogy between the oxymuriatic 

 and fluoric compounds, an analogy also suggested to him by M. Am- 

 pere. 



The experiments described in the present paper are principally 

 guided by this analogy, with a view to ascertain whether it is well 

 founded. 



The subjects of experiment are silicated fluoric gas, originally dis- 

 covered by Scheele. Liquid fluoric acid in its concentrated state, 

 first obtained by Messrs. Gay-Lussac and Thenard, and the fluo-boric 

 acid of the same chemists. 



When these compounds are acted upon by potassium or sodium, 

 the results are fluates of potash or soda, with silicum, hydrogen, or 

 boron, according to the compound operated upon. 



With regard to these results, there are three hypotheses which 

 may be maintained. One is, that fluoric acid consists of an inflam- 

 mable base united to oxygen. A second, that it consists of a simple 

 base, which may be called fluorine (analogous to chlorine), united with 

 hydrogen. A third is, according to the tenets of the phlogistians, 

 that fluoric acid, like metallic oxides, is liable to combine with hy- 

 drogen, and form an inflammable compound. Since all the pheno- 

 mena may be explained according to any one or other of these hy- 

 potheses, the sole question is, which of these explanations is best, as 

 being most conformable to the general series of chemical facts with 

 which we are at present acquainted. 



