CONCERNING FLUORINE. 39/ 



silicon the volatile tetrafluoride of silicon (SiF^). Davy suggested that vessels of 

 fluor-spar should be used for the decomposition, and the experiment has been 

 tried ; but the fluorides used were not perfectly dry, and the provoking element 

 united with the hydrogen of the water to form hydrofluoric acid. A German 

 scientist heated iodine with fluoride of silver in a glass tube and said he obtained 

 iodide of silver and a colorless gas, which he supposed to be fluorine; but the 

 English chemist Gore, who investigated the whole subject most carefully, found 

 that perfectly dry fluoride of silver is not decomposed under a red heat by chlo- 

 rine, bromine, or iodine ; while if a higher temperature is employed, a fluoride of 

 the metal — platinum, gold, silver, or whatever the vessel may be made of — is 

 formed. If tubes of graphite or charcoal are used, a fluoride of carbon is ob- 

 tained. The difficulty of making vessels of fluor-spar adapted to the purpose has 

 prevented further experiments with that material; and for the present the chem- 

 ists have to confess that they are baffled in all their attempts to isolate this singu- 

 lar element. 



Fluorine is also unique among the elements in not combining with oxygen. 

 It is remarkable that, with its powerful affinities for so many other elements, it 

 should be utterly indifferent to one which is equally omnivorous in its chemical 

 appetite. 



It has just been announced by foreign journals that Loew has discovered the 

 presence of free fluorine in a certain variety of fluor-spar, found at Wolsehdorf in 

 Bavaria. This spar is dark violet in color, and has a peculiar odor, which scient- 

 ists have attempted to explain by various theories, but not very satisfactorily. 

 Loew came to the conclusion that the odor might be due to free fluorine: and, to 

 test his hypothesis, he ground a kilogram of the Wolfsendorf spar with water con- 

 taining ammonia, using small portions at a time, the filtrate and wash-waters from 

 the earlier being used with the later quantities. The last filtrate was mixed with 

 sodium carbonate and evaporated ; the residue treated in a platinum capsule with 

 sulphuric acid, and, covered with a watch glass, kept at 40° to 50° C. for a long 

 time. On examining the glass it was found to be considerably corroded. Since 

 fluor-spar is not entirely insoluble in water, the experiment was repeated, using 

 the inodorous mineral. The result was so exceedingly feeble as to dispose en- 

 tirely of this objection to the former result. 



Since the odorous spar contains cerium, Loew believes that the free fluorine 

 is produced by the spontaneous change of eerie fluoride into cerous fluoride and 

 fluorine. We shall want, however, to know that his experiments have been re- 

 peated and verified by others before we believe in the free fluorine or accept this 

 theory of its origin. It would certainly be curious if an element which chemists 

 have made so many unavailing attempts to isolate is really found free in nature 

 under their very noses. Even if it is, the smell of it may be all that they v/ill 

 get in any attempt to collect and examine the gas. We shall see what we shall 

 see, as the pious Turks say. — Boston Journal of Chemistry. 



