120 MR. EDWARD SCHUNCK ON SOME 



gradually dissolved ; but on adding an excess of acid no 

 precipitate is produced, showing that a complete change 

 has taken place. In very dilute potash or soda-lye, as well 

 as in liquid ammonia, it dissolves readily on boiling. The 

 solutions when mixed with alcohol give colourless jellies, 

 consisting of the salts of the respective bases. If the pre- 

 cipitated ammonia-compound, after being filtered off and 

 washed with alcohol until the excess of ammonia is re- 

 moved, be treated with boiling water, it dissolves and the 

 solution leaves, on evaporation, a transparent, amorphous, 

 nearly colourless residue, which separates from the sides of 

 the vessel in shining scales. This residue dissolves again 

 entirely in water. The solution is neutral to test-paper, 

 and gives flocculent precipitates with alkaline salts, such as 

 chloride of sodium and chloride of ammonium, as well as 

 with all earthy and metallic salts which I have tried, ex- 

 cept per chloride of mercury and chloride of gold. The 

 precipitate with nitrate of silver, which is white, does not 

 change much when exposed for several days to light, and 

 when dissolved in ammonia yields a solution which on being 

 boiled becomes yellow but deposits no metallic silver. 

 When a solution of the acid in a sealed tube is heated for 

 some time in the water-bath, it is found to have under- 

 gone a complete change. The liquid leaves, on evapora- 

 tion, a brown, slightly deliquescent residue, which dissolves 

 again with ease in cold water. The solution has a strong 

 acid reaction. With caustic alkalies it strikes a deep 

 yellow colour. It gives flocculent precipitates with baryta- 

 water and acetate of lead, but none with hydrochloric acid 

 or chloride of sodium. With nitrate of silver it gives a 

 precipitate which blackens on exposure to light, and when 

 made alkaline it reduces oxide of copper at the boiling- 

 lieat. The acid has, in fact, been converted into the sub- 

 stance, or mixture of substances, to which Fremy has given 

 the name of metapectic acid. 



