10 Professor Berzeli us on [July, 



temperature at which, when it arrives, it effervesces, the cyanu- 

 ret is decomposed, and a great quantity of gas is disengaged 

 with rapidity. This gas is a mixture of sulphurous acid gas, 

 carbonic acid gas, and azote. The residual mass contains super- 

 sulphates of the bases employed and ammonia. 



Dr. Thomson asserts that on this occasion a new gas is formed, 

 and that this gas is composed of hydrogen, carbon, and oxygen, 

 the proportions of which he has apparently determined with 

 care. He has moreover given the specific gravity of this gas, 

 and determined the condensation of its elements at the moment 

 of their union. I have repeated the experiments of Dr. Thom- 

 son, according to the directions which he has given, and which 

 are rather indefinite. Of the gas which 1 obtained, 0*348 part 

 was absorbed by the black superoxide of lead, and 0-25 part by 

 caustic potash. The remainder, which contained the atmospheric 

 air of the apparatus before the commencement of the operation, 

 and the azotic gas which was not converted into ammonia, were 

 not inflamed by the electric spark, neither unmixed or mixed 

 with oxygen gas in different proportions. Lime-water was not 

 rendered at all turbid, and even when I added hydrogen gas and 

 inflamed the mixed gas, lime-water remained clear. I decom- 

 posed in the same mode the crystalline compound of sulphuric 

 acid and cyanuret of potassium and iron, and it gave me the same 

 products. The action of fire immediately decomposes it with rapi- 

 ditv, and afterwards a slower disengagement of gas takes place : 

 which happens when the sulphate of ammonia formed decomposes. 

 The gases which are then evolved are sulphurous acid and azote. 

 But even on this occasion no combustible gas was perceptible. 



I am now going to give a particular description of the com- 

 pounds of some cyanurets with sulphuric acid. 



1. Cyanuret of Iron and Fotassium with Sulphuric Acid. — 

 If the acid be added to the anhydrous cyanuret, it becomes very 

 hot, and if the acid be in sufficient quantity, the cyanuret is 

 totally dissolved, and after digesting for a few minutes, it gives 

 a clear and colourless solution. When left in an open vessel for 

 some days, the mass becomes pulpy, and filled with numerous 

 small annular crystals, surrounded with sulphuric acid less con- 

 centrated. I took this mass after eight days' exposure to the 

 air, and put it upon a brick, and placed it in vacuo, in order to 

 avoid the influence of atmospheric moisture upon the crystallized 

 part, and to facilitate the absorption of the liquid part. At the 

 expiration of 24 hours, I found upon the brick a white crystalline 

 mass composed of small interlaced acicular crystals. This mass 

 is soluble in water, and the solution has all the properties of one 

 ofsupersulphate of potash mixed with that of superhydrocyanate 

 of iron, which does not decompose by exposure to air, as it 

 would have done alone. Even alcohol of 0*81 density decom- 

 poses this salt, combining with the hydrocyanate of iron and the 

 sulphuric acid, and leaving the sulphate of potash. I analyzed 

 this compound in the following manner : I decomposed it by 



