Chemical Science. 161 



such quantity, that the liquid became a magma. These were 

 dried upon bibulous paper; they would not bear washing, the 

 affinity by which the compound was formed being so weak that 

 contact with water resolved it into pulverulent cyanuret of silver, 

 and solution of the nitrate, so that strong solution of nitrate of 

 silver is required in its preparation. When heated it fuses, 

 detonates, and leaves cyanuret of silver ; it contains no water. 

 If analogous to the preceding salt, it should contain 



Nitrate of Silver . . . 38.79 - 1 atom 

 Cyanuret of Silver . . 61.21 - 2 



100 



Equal to 70.76 per cent metallic silver. This statement was con- 

 firmed by the results of an experiment ; 0.43 of the compound de 

 composed by muriatic acid giving 0.387 chloride of silver, or 69.74 

 per cent, metallic silver. 



All attempts to form other similar compounds failed, the other 

 metallic cyanurets decomposing the nitrate of silver used in the 

 experiment. — Ann. Phil. N. S, ix. 131. 



21. Sulphates of Cinchonia and Quinia. — The following results 

 and remarks are abstracted from a inemoir by M. Baup. — Ann, 

 de Chimiey xxvii. 323. 



Svper Sulphate of Cinchonia. — Prepared by adding very pure- 

 sulphuric acid to the neutral sulphate, evaporating until a pellicle 

 forms, and setting it aside to crystallize. If the crystals are small 

 and fragile they should be re-crystallized ; if not soluble in 

 their weight of cold water, it is a proof that neutral sulphate is 

 present, when more acid must be added. This salt is colourless, 

 unaltered at common temperatures in the air, but readily efflo- 

 rescing if the tempera,Jure be slightly raised ; crystals are rhom- 

 boidal octoedra, always imperfect, and readily cleaving perpen 

 dicularly to the larger axis. It is soluble in 0.46 of water at 57°.2, 

 or in 0.9 of alcohol, specific gravity 0.85. Ether does not dis- 

 solve it. 



Neutral Sulpliate of Cinchonia. — Crystals short rhomboida) 

 prisms of 83° and 97° cleaving parallel to the planes of the 

 prism, soluble in 6.5 of alcohol, specific gravity 0.85 at 5 5®. 4, or 

 in 11.5 of absolute alcohol, or in 54 of water. 



The elements of these salts were estimated as follows : — Tlie 

 water from the loss occasioned by exposure in a stove, at a tem- 

 perature of 248° Fahr. until no further diminution took place ; the 

 sulphuric acid by precipitation from a solution of the sulphate in 

 diluted acetic acid, by muriate of baryta ; the cinchonia by the defi- 

 ciency. From these experiments it was deduced that 39 would 



Vol. XIX. M 



