MR. €k GORE ON HYDROFLUORIC ACID; 
187 
aeicl in a cool place. On loosening the lid of a bottle of the acid at 60° Fahr., the acid 
vapour is expelled in a jet like steam from a boiler. 
The low boiling-point, the extremely dangerous and corrosive nature of the acid, and 
ts great affinity for water, illustrate the very great difficulty of manipulating with it and 
retaining it in a pure state; nevertheless by the contrivance described (see page 175), 
and placing the bottles containing it in a cool cellar (never above a temperature of 60° 
Fahr.), the author has succeeded in keeping the liquid acid perfectly, without loss, and 
unaltered through the' whole qf the recent hot summer. 
The following is the order of electrical relation found with different metals &c. in 
the pure anhydrous acid at 0° Fahr. : — zinc, tin, lead, cadmium, indium, magnesium, 
cobalt, aluminium, iron, nickel, bismuth, thallium, copper, iridium, silver, gas-carbon, 
gold, platinum, palladium. The acid in these experiments was contained in a covered 
deep and narrow" platinum cup placed in a tin chilling case immersed deeply in the 
freezing-mixture. 
Sir H. Davy electrolyzed the liquid acid prepared by distilling fluor-spar with strong 
sulphuric acid. lie cemented a platinum wire by fusion into a cup of horn silver, and 
inverted the cup in the acid in a tray of platinum. He used a very weak voltaic current, 
and kept the apparatus cool by a freezing-mixture. The platinum wire rapidly corroded 
and became covered with a chocolate-coloured powder. Inflammable gas like hydrogen 
was evolved from the cathode. He also tried a plumbago anode, but it was quickly 
destroyed and the liquid became turbid and black; also a charcoal anode upon the end 
of a platinum wire ; the charcoal absorbed the acid and made the platinum wire the pole*. 
G. J. Khroxf also electrolyzed hydrofluoric acid with a charcoal anode attached to a 
platinum wire, and a platinum wire cathode, in a vessel of fluor-spar half filled with the 
acid, and having a perforated stopper of the same spar dipping into the acid. It is not 
stated in the above paper how the acid was prepared or its purity determined, nor by 
what means charcoal capable of resisting the acid was obtained. 
I have made numerous experiments of electrolyzing the pure anhydrous acid with 
various electrodes. The method adopted in many of the experiments was to place a 
platinum cup about inches ( = 9 centims.) deep and If inch ( = 4’5 centims.) wide 
in a tin case (weighted with lead) in the freezing-mixture ; the cup was about half filled 
with the acid, and was closed by a well-fitting stopper of paraffin, through the centre 
of which a long rod or plate of the substance constituting the anode was closely fixed, 
the cup itself being the cathode ; a loosely fitting cup of paraffin about half an inch 
deep, and provided with a handle, was immersed in the acid beneath the anode to collect 
particles which fell from the anode, and to prevent hydrogen ascending from the bottom 
of the platinum vessel and coming into contact with the positive electrode. The follow- 
ing are some of the results obtained. The liquid acid conducted with a platinum anode 
much more readily than pure water ; with four Smee’s elements it began to visibly 
* Works of Sir 3L Davy, vol. v. p. 416. 
t Philosophical Magazine, 3rd series, vol. xvi. p. 192. 
