[ 515 j 



LXX. Chemical Notices from Foreign Journals. 

 By E. Atkinson, Ph.D., F.C.S. 



[Continued from p. 385.] 



PROF. SCHROTTER has described* the occurrence of ozone 

 in a specimen of fluor-spar which is found at Wulsendorf. 

 It is a darkish-blue variety, and when scratched or rubbed in a 

 mortar, it emits a powerful odour closely resembling that of 

 bleaching powder. The phenomenon has long been known, and 

 has been ascribed to the presence of chlorous acid. 



On rubbing the mineral in a mortar, Schrotter observed that 

 the odour emitted was exceedingly like that of ozone. When it 

 was triturated in a mortar with iodide of potassium solution, the 

 liquor became brown from the liberation of iodine, and when a 

 piece of ozone test-paper was held over the mortar it became di- 

 stinctly blue. This reaction might, however, have been produced 

 either by a chlorine compound or by ozone. But when tritu- 

 rated with water or with alkalies, although a powerful smell was 

 produced, no trace of a chlorine compound could be detected in 

 the liquid. 



When the mineral was triturated with chloride of sodium, 

 chlorine was liberated, as was evident from the smell, and also 

 by the fact that the reaction for chlorine was obtained when a 

 plate moistened with nitrate of silver was held over the mixture. 

 This must have been due to ozone, which has the property of 

 expelling chlorine from its compounds ; it is inconceivable that 

 any oxygen compound of chlorine could have the property of 

 liberating chlorine under these circumstances. Besides, the 

 mineral, when triturated with pure wood-charcoal, emitted no 

 odour, while, as a control experiment showed, the reverse is the 

 case with hypochlorite of lime. 



When the mineral was heated, a strong odour was perceived, 

 which afterwards disappeared. Heated more strongly it lost its 

 dark-blue colour, and appeared of a reddish-brown colour from 

 sesquioxide of iron. 



The following experiment was conclusive as to the absence of 

 chlorine : — The anterior part of a piece of combustion tubing 

 was filled with pieces of the mineral, while the rest of the tube 

 contained pieces of porcelain. A potash apparatus containing 

 iodide of potassium and starch was fitted to the posterior part of 

 the tube. The part containing the mineral was gently warmed, 

 and the rest of the tube was heated to redness, while at the same 

 time purified air was passed through the tube. No liberation of 

 iodine was observed in the potash apparatus. Had any one of the 

 oxygen compounds of chlorine been present, in its passage over 



* Sitz.-Ber. der Wiener Akademie, vol. xli. 



