96 Mr. Faraday on the [Feb. 



where the euchlorine previously lay, but the fluid had all disap- 

 peared. 



Nitrous Oxide. 



Some nitrate of ammonia, previously made as dry as could be 

 by partial decomposition, by heat in the air, was sealed up in a 

 bent tube, and then heated in one end, the other being preserved 

 cool. By repeating the distillation once or twice in this way, it 

 was found, on after-examination, that very little of the salt 

 remained undecomposed. The process requires care. I have 

 had many explosions occur with very strong tubes, and at consi- 

 derable risk. 



When the tube is cooled, it is found to contain two fluids, and 

 a very compressed atmosphere. The heavier fluid on examina- 

 tion proved to be water, with a little acid and nitrous oxide in 

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

 liquid, limpid, colourless state ; and so volatile that the warmth 

 of the hand generally makes it disappear in vapour. The appli- 

 cation 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 immediately burst 

 into vapour. Another tube opened under water, and the vapour 

 collected and examined, it proved to be nitrous oxide gas. A 

 gage being introduced into a tube, in which liquid nitrous oxide 

 was afterwards produced, gave the pressure of its vapour as equal 

 to above 50 atmospheres at 45°. 



Cyanogen. 



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, while the other end was cooled. 

 The cyanogen soon appeared as a liquid : it was limpid, colour- 

 less, 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 expan- 

 sion within did not appear to be very great ; and the liquid 

 passed with comparative slowness into the state of vapour, pro- 

 ducing great cold. The vapour, being collected over mercury, 

 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 



