Messrs. Knox on the hisulation of Fluorine. 129 



ceivers, when filled with the gas, could be slid. The results we came to with these 

 vessels were the following : — Litmus paper was reddened, glass strongly acted upon, 

 gold on one occasion slightly acted upon, owing, as we believe, to the formation 

 of a fluoride of gold, as we were led to suppose by the action of the product on 

 glass, when heated with sulphuric acid. From having ascertained the perfect 

 dryness of the materials, and from the absence of moisture when the cover had 

 been cooled down by the evaporation of sulphuret of carbon, we proved the 

 absence of hydro-fluoric acid ; and from having obtained bi-chloride of mercury, 

 we inferred the disengagement of fluorine. These reasons alone, we conceived, 

 would have been sufficient to justify us in supposing the insulation of fluorine. 



It may be mentioned here, that after we had entered on our investigations, 

 we met with a notice of some experiments made by M. Baudrimont, with 

 the intention of insulating fluorine in glass vessels. He heated a mixture of 

 fluor-spar and peroxide of manganese with sulphuric acid in a glass retort, and 

 collected in a dry glass vessel a gas of a yellowish brown colour, which bleached 

 litmus paper, and acted upon gold in the cold, differing from the gas that we have 

 obtained in these qualities. 



In the month of December last we had other fluor vessels constructed at 

 Mavve's establishment, of a similar form to those already employed, but much 

 larger size ; they were lapped with fine iron wire, were of a very consider- 

 able thickness, and could contain about four fluid ounces ; the upper part of 

 these vessels was turned round, and reduced in thickness, so as to fit into a flat 

 slab of fluor-spar, and the upper edge of the vessels was then polished off", so as 

 to be on the same level with the flat slab, which acted as a table upon which the 

 covers of the vessels and the receivers for the gas could be slid, without letting 

 the contents mix with the atmospheric air. The receivers for the gases were 

 square, about two inches and a half high, and one and a quarter wide, and the 

 interior, which was circular, and about five-eighths of an inch in diameter, was 

 fitted with a stopper of fluor. On opposite sides of these receivers {see Plate) 

 holes were drilled quite through, intersecting the former cavity at right angles, 

 and into these holes were fitted, air-tight, clear crystals of fluor, so that the 

 colour of any gas in the receiver could be distinctly observed on looking through 

 them. There were some small depressions in the flat slab, which we have above 

 called the table, in which might be placed any piece of metal or other substance 



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