332 
ME. GEOEGE GOEE ON FLUOEIDE OF SILYEE. 
intensely dusty odour, which fumed very strongly in the air, was heavy, and might be 
poured. The iodine cup was empty, the other contained the usual yellow residue, most 
of which had been fused by heat applied in extracting the stopper. On heating the 
cups gradually to redness, the fuming vapour and free iodine were expelled. The saline 
residue after fusion weighed 126'73 grains =8T4 grains of fluorine expelled. The 
cups were not corroded. 
To try the effect of a higher temperature, I employed a platinum retort of the form A, 
fig. 10, 153 millims. long and 22 millims. diameter, with an air-tight stopper B, and a thick 
Fig. 10. Fig. 11. 
platinum bottle C with a wide mouth, to contain the fluoride, and an arrangement (fig. 11) 
to secure the stopper. 29'83 grains of fluoride and 35'33 grains of iodine were taken; 
and nearly half the retort was placed horizontally in a hole in a block of cast iron, and 
kept at 600° Fahr. during ten hours, with frequent rotation. The temperature was 
partly determined by means of a bit of cadmium placed upon the block. No leakage 
occurred ; and no tension of vapour was found on opening the cooled retort. The results 
were similar to those of the last experiment. By fusing the saline residue it lost 
18'36 grains, and then weighed 46'80 grains = 2'98 grains of fluorine expelled. The 
bottle was slightly corroded and had lost '35 grain in weight. 
In a second experiment with this retort, 46'73 grains of fluoride and 34'98 grains of 
iodine were taken, and the retort heated to about 720° Fahr. during fifteen hours. The 
results were again similar. All the free iodine had been absorbed by the saline residue. 
The silver-salt after fusion weighed 67*81 grains = 3*708 grains of fluorine expelled. 
The bottle lost T20 grain in weight. After a third experiment, with much larger 
quantities of materials at a still higher temperature, much fuming iodine remained, 
and a platinum boat containing the fluoride had lost 9 '6 3 grains in weight. 
From these experiments it is evident that platinum is corroded by contact with iodine 
and argentic fluoride at a temperature of 700° Fahr. 
I also passed vapour of recently fused iodine during two hours over 135 '2 9 grains of 
previously melted fluoride in the same apparatus and manner as in the experiments with 
bromine (see page 326). An acid odour was evolved, and a vapour which corroded glass 
quickly, but no sublimate except iodine appeared ; the sublimed iodine fumed strongly 
in the air. After heating the platinum apparatus to redness the gain of weight was 
89'62 grains, =104’568 grains of the fluoride decomposed and its fluorine expelled, if 
we allow 4'65 grains of iodine taken up by 3*96 grains of free silver in the original 
fused fluoride (see analysis of fluoride of silver, Phil. Trans. Boy. Soc. 1870, p. 229). 
