326 
MR. GEORGE GORE ON FLUORIDE OF SILVER. 
very slowly decomposed by that gas at 60° Fahr. with superficial formation of silver 
chloride. 
With Chloric Acid . — A saturated aqueous solution of argentic fluoride manifested no 
signs of chemical change on the addition of aqueous chloric acid. 
With Bromine . — The behaviour of argentic fluoride with bromine is generally similar 
to that with chlorine. 5‘07 grains of earthy fluoride of silver in a closed glass bottle 
containing common liquid bromine, exposed during two days to sunlight, gained 1T5 
grain in weight, theory requiring 2‘43 grains if it had been wholly converted into 
bromide and its fluorine expelled. 
A platinum cup containing 75T3 grains of recently fused argentic fluoride was placed 
in an inverted dry glass bottle ; and within the cup was placed a small platinum crucible 
containing 42T6 grains of dry bromine which had been twice redistilled with fragments 
of fused chloride of calcium, and the last portions rejected. The stopper of the bottle 
having been firmly secured, the mouth of the bottle was immersed in mercury, and the 
whole set aside during thirty-six days at atmospheric temperature. Much free bromine 
still remained. The argentic salt had gained only ‘38 grain in weight, and remained 
almost entirely soluble in water. In another similar experiment in which the liquid 
bromine was in contact with a larger surface of the silver-salt, similar results occurred. 
Bromine, therefore, has but little action on fused argentic fluoride at 60° Fahr. 
To ascertain the effect of a higher temperature, two platinum cups were placed in a 
securely stoppered bottle inverted 3 inches deep in mercury with the mouths of the cups 
upwards. One cup contained 66'24 grains of the recently fused fluoride, and the other 
28 - 64 grains of the redistilled and perfectly dry bromine. After standing six days at 60° 
Fahr., a gentle heat was applied ; a small leakage of vapour occurred. After standing 
twenty-four more days at 60° Fahr., the bottle was again heated during two days to about 
200° Fahr. ; a small leakage again took place during the first few hours of heating. At 
the end of the twenty-four hours the colour of bromine had entirely disappeared, and the 
bottle was only slightly corroded. The bottle was again heated to 200° Fahr. during 
four days more and then cooled. Much bromide of mercury had formed around the 
outside of the stopper. The surface of the saline residue was yellow ; and the cup and 
silver-salt had gained only 1 ‘37 grain in weight. By digesting the residue in hot dilute 
nitric acid, about 3^ grains of insoluble bromide was formed ; the soluble portion yielded 
by analysis 71 '83 grains of argentic fluoride = 6 3*57 grains of fluoride of silver undecom- 
posed. Bromine, therefore, acts slowly upon argentic fluoride at 200° Fahr., but less 
slowly than chlorine acts upon it. 
Ordinary bromine, which had been rendered anhydrous, was passed during one hour 
over 5T88 grains of fluoride of silver at a low red heat in a platinum boat inside a short 
platinum tube within a longer one ; a second platinum boat containing the bromine 
being placed near the first one, and the contiguous end of the long tube closed by a 
stopper of platinum, the heat extended to the bromine and produced a continuous supply 
of vapour. During the early part of the experiment a gas was evolved which corroded 
