ME. GEOEGE GOEE ON FLUOE1DE OE SILVER, 
239 
if any moisture had been present. No special corrosion of any of the vessels occurred. 
From these results, supported by other reasons, I consider that a double fluoride of 
hydrogen and silver exists, similar to the corresponding salt of hydrogen and potassium, 
but more easily decomposable by heat. The non-reduction of any of the heated salt to 
metal affords further confirmation of the fact that the liquid expelled by heat from the 
acid fluoride of potassium is quite free from Avater (see Phil. Trans. Roy. Soc. 1869, 
pp. 184 & 185). 
With Chlorine. — Several investigators have subjected argentic fluoride to the action of 
chlorine. Aime* passed chlorine over the salt at 60° Fahr. Sir H. DAVYf heated per- 
fectly dry fluoride of silver in a glass vessel filled with chlorine ; the salt was converted 
into chloride, the retort was violently corroded, much chlorine was absorbed, fluoride of 
silicon and free oxygen Avas produced, but no neAV gas was discovered. 
The brown fluoride, in the proportion of 6 grains to each ounce of chlorine, Avas 
exposed to the sun’s rays in a bottle full of that gas in the dry state ; the yelloAv colour 
of the gas disappeared, and strong rarefaction Avas found on opening the vessel. 
A glass receiver A (see p. 236), of 262 cub. centims. capacity, was filled Avith dry chlorine. 
A stout tube B of refractory glass (lined within its outer half Avith a sheet of platinum), 
containing a platinum boat Avith an equivalent quantity of recently fused argentic fluoride, 
was fixed to the globe air-tight byaAvasher of vulcanized india-rubber coated with paraffin 
The neck of the globe Avas closed by a cork coated with paraffin and immersed in mercury. 
A gentle red heat was applied to the boat, and the tubulure was kept cold by a stream 
of water. The yellow colour of the gas disappeared in less than one hour, and the heat 
was continued 3f hours. The receiver Avas then opened under mercury, on doing which 
the mercury entered Avith force until it filled about -f of the vessel. The mercury 
acquired a slight film as if a little free chlorine still remained. The level of the mercury 
was not loAvered by now applying a Ioav red heat to the boat. No leakage of gas took 
place, and the bottle Avas comparatively but little corroded. 
In a second similar experiment the retort was of platinum constructed Avithout solder. 
59 grains of the fused fluoride was employed, and a red heat applied during one hour and 
twenty-two minutes. The colour disappeared in three quarters of an hour, and no leakage 
of gas took place. On admitting the mercury it immediately filled the apparatus within 
41 cub. centims. of its capacity at standard pressure. The boat Avas much corroded, and 
the contents of the tube had gained 9 - 5 grains in weight, the missing chlorine being 
22F2 cub. centims. = 10-3 grains. By heating the retort to redness its contents lost 
1-06 grain; and an acid fuming vapour (probably fluoride of silicon) Avas evolved, Avhich 
extinguished a red-hot splint. 
To exclude the interferences caused by corrosion of the glass, I liaA^e employed an 
apparatus composed entirely of platinum, its parts being constructed Avithout solder; it 
* Giielix’s Handbook of Chemistry, vol. ii. p. 359 ; Annal. de Chimie, vol. lv. (1833) p. 443 ; Liebig’s Annal, 
vol. xvi. (1835) p. 174; Poggendorff’s Annalen, vol. xxxii. (1834) p. 576. 
f Sir II. Davy’s Works, v. p. 416. 
- f Paraffin protects vulcanized india-rubber bungs very effectually from injury by chlorine. 
2 i 2 
