548 Royal Society : — Mr. G, Gore on the 



brown colour, and dissolved in water, producing a pink solution with 

 separation of black oxide. Peach-coloured carbonate of cobalt evolved 

 no visible gas in the liquid acid ; it became greenish blue, but did 

 not lessen in bulk in three days ; the residue became pink in the air, 

 and dissolved almost completely in water, forming a pink liquid ; it 

 also dissolved in dilute hydrochloric acid without evolving bubbles of 

 gas. Anhydrous chloride of nickel did not dissolve in the liquid acid 

 in six days. Metallic copper soon lost its brightness in the gas; it 

 evolved no gas in the liquid acid, and was only slightly corroded after 

 seven days. Black oxide of copper became of a lighter colour in the 

 liquid acid, but did not lessen in bulk in seven days ; the residue 

 was a greenish and yellowish white powder, which instantly turned 

 black in water, forming a pale-blue solution, and left black oxide of 

 copper. A crystal of blue vitriol became of a light brown colour 

 in the liquid acid, but did not dissolve in six days ; on removal it 

 was found to be a brown soft solid. Protoxide of mercury became 

 white in the gas, and did not dissolve by constant immersion in the 

 liquid acid in four days ; the residue was a white solid, soluble in 

 water. Vermilion in powder slowly changed in the liquid acid in 

 three days to a pinkish-white solid, but did not dissolve. Scarlet 

 iodide of mercury in powder imparted a red colour to the liquid 

 acid, but did not lessen in bulk or change in colour during 

 three days ; the residue lost its red colour on the application of 

 heat. A fragment of protochloride of mercury did not visibly alter 

 in the liquid acid in four days. Metallic silver did not dissolve or 

 become much corroded during seven days. Oxide of silver became 

 white in the liquid acid in one day, but did not dissolve. Precipi- 

 tated chloride of silver in powder did not visibly alter or dissolve 

 during sixteen days. Metallic platinum was unaffected in the liquid 

 acid. 



Oxalic acid was slightly dissolved in the liquid acid in three days 

 without change of colour. Uric acid remained undissolved and un- 

 changed during three days. Paraffin did not appear to be dissolved 

 or affected in nine days. Gutta percha was quickly acted upon; it 

 imparted to the liquid acid, first a red, and ultimately a dark-brown 

 colour ; it appeared also to dissolve in the acid to some extent, and 

 on discharging the tubes was left behind as a tenacious coating upon 

 the adjacent parts. Gun-cotton was unaffected in the liquid acid. 

 Cotton was not visibly altered in two days. Solid extract of litmus 

 dissolved slightly, forming a faintly purple blue or inky solution ; it 

 became of a dark red colour and enlarged in bulk ; the residue 

 formed a perfect solution in water ; the solution was red in colour. 



Remarks. — The foregoing experiments show that liquid hydro- 

 chloric acid has but a feeble solvent power for solid bodies in general. 

 Out of 86 solids it dissolved only 12, and some of those only in a 

 minute degree; of 5 metalloids it dissolved 1, viz. iodine; of 15 

 metals it dissolved only 1, viz. aluminium ; of 22 oxides it dissolved 

 5, viz. titanic acid, arsenious acid, arsenic acid, teroxide of antimony, 

 and oxide of zinc ; of 9 carbonates it dissolved none ; of 8 sulphides 

 it dissolved 1, viz. tersulphide of antimony; of 7 chlorides it dis- 



