258 Mr. G. Gore on Hydrofluoric Acid. [Jan. 28, 



be as follows at 0° Fahr. : — zinc, tin, lead, cadmium, indium, magnesium, 

 cobalt, aluminium, iron, nickel, bismuth, thallium, copper, iridium, silver, 

 gas-carbon, gold, platinum, palladium. 



Numerous experiments were made of electrolyzing the anhydrous acid 

 with anodes of gas-carbon, carbon of lignum-vitse and of many other kinds 

 of wood, of palladium, platinum, and gold. The gas-carbon disintegrated 

 rapidly ; all the kinds of charcoal flew to pieces quickly ; and the anodes of 

 palladium, platinum, and gold were corroded without evolution of gas. The 

 acid with a platinum anode conducted electricity much more readily than 

 pure water ; but with one of gold it scarcely conducted at all. These elec- 

 trolytic experiments presented extreme difficulties, and were conducted 

 in a platinum apparatus (shown by a figure) specially devised for the 

 purpose. The particulars of the conditions and results obtained are de- 

 scribed in the paper. Various mixtures of the anlrydrous acid with 

 monohydrated nitric acid, with sulphuric anhydride, and with monohy- 

 drated sulphuric acid were also electrolyzed by means of platinum anodes, 

 the particulars and results of which are also described. 



To obtain an idea of the general chemical behaviour of the pure anh}'- 

 drous acid, numerous substances (generally anhydrous) were immersed in 

 separate portions of the acid in platinum cups, kept at a low temperature 

 (0° to —20° Fahr.). The acid had scarcely any effect upon any of the me- 

 talloids or noble metals ; and even the base metals in a state of fine powder 

 did not cause any evolution of hydrogen. Sodium and potassium behaved 

 much the same as with water. Nearly all the salts of the alkali and alka- 

 line-earth metals produced strong chemical action. Various anhydrides 

 (specified) dissolved freely. Strong aqueous hydrochloric acid produced 

 active effervescence. The alkalies and alkaline earths united strongly with 

 the acid. Peroxides gave no effect. Numerous oxides (specified) produced 

 strong chemical action, some of them dissolving. Some nitrates were not 

 chemically affected ; others (those of lead, barium, and potassium) were 

 decomposed. Fluorides generally were unchanged ; but those of the alkali- 

 metals and of thallium produced different degrees of chemical action, 

 those of ammonium, rubidium, and potassium uniting powerfully. Nume- 

 rous chlorides were also unaffected, whilst those of phosphorus (the solid 

 one only), antimony (the perchloride), titanium, and of the alkaline-earth 

 and alkali metals, were decomposed with strong action, and generally with 

 effervescence. The chlorates of potassium and sodium were also decom- 

 posed with evolution of chloric acid ; the bromides of the alkaline-earth 

 and alkali metals behaved like their chlorides. Bromate of potassium 

 rapidly set free bromine. Numerous iodides were unaffected ; but those of 

 the alkaline-earth and alkali metals were strongly decomposed, and iodine 

 (in some cases only) set free. The anhydrous acid decomposed all carbonates 

 with effervescence, and those of the alkaline-earth and alkali metals 

 with violent action. Borates of the alkalies also produced very strong 

 action. Silico-fluorides of the alkali metals dissolved with effervescence. 



