394 Proceedings of Philosophical Societies. [May, 



flow upon the sulphuret, and, in space of 24 hours, protomuriate 

 of iron, and liquid sulphuretted hydrogen, were formed. When 

 the tube was broken, under water, a portion of the gas which 

 arose was collected, and found to be pure sulphuretted hydrogen, 

 with which, also, the water was found to be impregnated. Sul- 

 phuric ether, when compared with this liquid, appeared adhesive 

 and oily ; the pressure which its vapour exerts, in the tube, is 

 equal to 13 atmospheres, at 32* F. Liquid carbonic acid was 

 produced in a similar manner, by means of sulphuric acid and 

 carbonate of ammonia ; but the strongest tubes were required 

 for its formation, and tubes which had contained it for several 

 weeks, often exploded with great violence upon a slight change 

 of temperature. It was necessary to use a glass mask, goglers, 

 &c. in the whole of these experiments ; and some of them were 

 attended with much risk to the author. The refractive power 

 of liquid carbonic acid is much less than that of water ; the pres- 

 sure exerted by its vapour is equal to 40 atmospheres at about 

 45°. Euchlorhie was liquefied, by its evolution, in a sealed tube, 

 from chlorate of potash and sulphuric acid ; in this state, it is of 

 a deep-yellow colour, and quite transparent. 



Some nitrate of ammonia, previously rendered as dry as pos- 

 sible by being heated to partial decomposition, was heated in a 

 closed tube ; and the results were, liquid nitrous oxide and water : 

 the two fluids did not mix, or but in a slight degree. The refrac- 

 tive power of liquid nitrous oxide is lower than that of any of these 

 fluids, and lower, indeed, than that of any other known liquid. 

 Its vapour exerts a pressure equal to 48 atmospheres at 50°. 

 Liquid cyanogen was formed by heating cyanuret of mercury ; 

 when the tube was broken, it became pure cyanogen gas. 



The liquefaction of ammoniacal gas was effected by heating a 

 portion of chloride of silver which had absorbed a large quantity 

 of it, according to a property of this and of other chlorides 

 formerly ascertained by the author. In this experiment, a 

 curious combination of effects took place ; as the tube cooled, 

 the chloride began to re-absorb the ammonia, by the solidification 

 of which, heat was liberated ; while, at the distance only of a 

 few inches, at the opposite end of the tube, cold was produced 

 by the consequent evaporation of the liquid. At 60°, the whole 

 of the ammonia became re- absorbed. The refractive power of 

 liquid ammonia exceeds that of any other liquid described in 

 this paper, and is even greater than that of water. Liquid 

 muriatic acid, when the substances from which it is prepared are 

 pure, is colourless, as Sir H. Davy had anticipated : its refrac- 

 tive power is nearly that of liquid carbonic acid. 



All these liquids, with the exception of chlorine and euchlo- 

 rine, are colourless ; all are perfectly transparent, and highly 

 fluid, and remain so at all temperatures to which they have been 

 subjected ; none of them exhibiting the least tendency to adhe r 



