356 Abstract of Mr, Faraday*s Experiments on the 



tillation once or twice in this way, it was found, on after-ex- 

 amination, that very little of the sah remained undecompo- 

 sed. The process requires care- I have had many explo-^ 

 sions occur with very strong tubes, and at considerable risk» 

 " When t4ie tube is cooled, it is found to contain two 

 fluids, and a very compressed atmosphere. The heavier, 

 fluid, on examination, 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 application of ice and salt con- 

 denses 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 been yet obtained in 

 these experiments, or than any known fluid. ,,A tube being 

 opened in the air, the nitrous oxide immediately burst into 

 vapour. 



The pressure of its vapour is equal to above fifty atmos- 

 pheres at 45°. 



''^Cyanogen. — Some pure cyanuret of mercury was heated 

 until perfectly dry. A portion was then inclosed in agreen 

 glass tube, in the same manner as in the former instances, and 

 being collected to one end, was decomposed by heat^ 

 whilst the other end was cooled. The cyanogen soon ap- 

 peared as a liquid : it was limpid, colourless and very fluid; 

 not altering its state at the temperature of 0°. Its refrac- 

 tive power is rather leirs, 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 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 be. In the course of some days, ac- 

 tion had taken place, the water had become black, and 

 changes, probably such as are known to take place in as 



