394 FLUORINE. 



I C1 5 . When treated in the dry state with anhydrous alcohol or 

 ether, these menstrua take up hydrochloric acid and chloride 

 of iodine, leaving iodic acid white and pulverulent. 



Bromides of iodine. Iodine likewise forms two bromides, 

 which are both soluble in water. The solution bleaches litmus 

 paper without first reddening it. 



SECTION XIII. 



FLUORINE. 

 Eq. 233.8 or 18.74 ; F; density (hypothetical) 1292; Qj- 



This elementary body is most frequently found in the mineral 

 kingdom in combination with calcium, or as fluoride of calcium, 

 which constitutes the mineral, fluor spar, and exists in small 

 quantity in amphibole, mica and most of the natural phos- 

 phates; a trace of it also occurs in the enamel of the teeth, and 

 in the bones of animals. Of all bodies, fluorine appears to pos- 

 sess the most powerful and general affinities, and to be, there- 

 fore, the most difficult to isolate, or to preserve for the study of 

 its properties. Indeed we have hitherto learned little more of 

 fluorine than that it exists and may be isolated. Several of its 

 compounds, however, are of less difficult preparation and well 

 known. 



Sir H. Davy made several attempts to isolate fluorine. He 

 exposed the fluoride of silver in a glass tube to gaseous chlorine, 

 at a high temperature, and found that chloride of silver was 

 produced, and fluorine therefore liberated, but it was absorbed 

 and replaced by oxygen, which it disengaged from the silica and 

 soda of the glass. When Davy repeated the same experiment 

 in a platinum vessel, the metal became covered with fluoride of 

 platinum. He proposed afterwards to construct vessels of fluor 

 spar for the reception of the fluorine, which he expected to dis- 

 engage from the fluoride of phosphorus by burning it in oxygen, 

 gas; but he does not appear to have carried this project into ex- 

 ecution, and it is to be feared that any such operation, in which 

 an excess of chlorine is necessarily employed, would yield a 

 chloride of fluorine, rather than pure fluorine. M. Baudrimont 

 avoided the use of chlorine, and transmitted the volatile fluoride 

 of boron over deutoxide of lead (minium) in an ignited porcelain 



