200 
ME. G. GOEE ON HYDEOELUOEIC ACID. 
chloric acid before water in electrolysis. Only a trace of chloride of platinum was 
formed at the anode in four hours, and the anode was not visibly corroded. With equal 
volumes of aqueous hydrofluoric and strong sulphuric acids much gas and a strong odour 
of ozone was evolved from the anode ; hydrogen also from the cathode. The anode 
corroded very slowly, without being covered with an insoluble film, and the liquid 
became cloudy with suspended particles, which were light brown at first, then brown, 
and after many hours’ action nearly black. The fumes from this mixture rapidly black- 
ened gutta percha. With hydrofluoric acid containing much selenious acid dissolved in 
it, gas was evolved from both electrodes, and a liberal deposit of red selenium formed 
at the cathode. No odour of ozone occurred until a large quantity of red and black 
selenium (probably nearly all) was deposited upon the sides and bottom of the platinum 
cup, then ozone occurred strongly. The anode was not visibly corroded in twenty-eight 
hours’ active electrolysis. The solution was filtered and evaporated to a small bulk ; it 
then fumed densely : the odour was like that of hydrofluoric acid, and when cold the 
liquid was odourless and of a somewhat oily consistence. The final liquid evolved a 
little heat on adding water to it. I found traces of platinum in the deposited selenium. 
With aqueous hydrofluoric acid, to which some phosphoric anhydride had been freely 
added, ozone was evolved from the anode, and hydrogen from the cathode ; the anode 
was slowly corroded, and a small quantity of black precipitate formed ; the liquid 
remained nearly colourless. 
