of several Gases into Liquids. 421 



oxide in solution ; the other was nitrous oxide. It appears in 

 a very hquid, limpid, colourless state; and so volatile that the 

 warmth ot" the hand generally makes it disappear in vapour. 

 The application of ice and salt condenses abundance of it into 

 the liquid state again. It boils readily by the difference of 

 temperature between 50° and 0°. It does not appear to have 

 any tendency to solidify at —10°. Its refractive power is very 

 much less than that of water, and less than any fluid that has 

 yet been obtained in these experiments, or than any known 

 fluid. A tube being opened in the air, the nitrous oxide im- 

 mediately burst into vapour. Another tube opened under 

 water, and the vapour collected and examined, it proved to 

 be nitrous oxide gas. A gauge being introduced into a tube, 

 in which litiuid nitrous oxide was afterwards produced, gave 

 the pressure of its vapour as equal to above 50 atmospheres 

 at 45°. 



Ci/a7ioge?i. 



Some pure cyanuret of mercury was heated until perfectly 

 dry. A portion was then inclosed in a green glass tube, in 

 the same manner as in former instances, and being collected 

 to one end, was decomposed by heat, whilst the other end was 

 cooled. The cyanogen soon appeared as a liquid : it was 

 limpid, colourless, and very fluid ; not altering its state at the 

 temperature of 0°. Its refractive power is rather less, perhaps, 

 than that of water. A tube containing it being opened in the 

 air, the expansion within did not appear to be very great; 

 and the liquid passed with comparative slowness into the state 

 of vapour, producing great cold. The vapour, being collected 

 over mercuiy, proved to be pure cyanogen. 



A tube was sealed up with cyanuret of mercury at one end, 

 and a drop of water at the other; the fluid cyanogen was 

 then produced in contact with the water. It did not mix, at 

 least in any considerable quantity, with that fluid, but floated 

 on it, being lighter, though apparently not so much so as 

 ether would be. In the course of some days, action had taken 

 place, the water had become black, and changes, probably 

 such as are known to take place in an aqueous solution of cy- 

 anogen, occurred. The pressure of the vapour of cyanogen 

 appeared by the gauge to be fi'6 or 3'7 atmospheres at 45° F. 

 Its specific gravity was nearly 0*9. 



yl»i7nonia. 

 In searching after liquid anmionia, it became necessary, 

 tlunigh difficult, to find some dry source of that substance ; 

 and I at last resorted to a compound of it which I had occa- 

 sion 



