1824.] Liquefaction of Chlorine and other Gases. 91 



over a bath of sulphuric acid before it was introduced. Upon 

 throwing in air and giving pressure, there was now no solid film 

 formed, but the clear yellow fluid was deposited, aud more 

 abundantly still upon cooling. After remaining some time it 

 disappeared, having gradually mixed with the atmosphere above 

 it, but every repetition of the experiment produced the same 

 results. 



Presuming that I had now a right to consider the yellow fluid 

 as pure chlorine in the liquid state, I proceeded to examine its 

 properties, as well as I could when obtained by heat from the 

 hydrate. However obtained, it always appears very limpid and 

 fluid, and excessively volatile at common pressure. A portion 

 was cooled in its tube to 0° : it remained fluid. The tube was 

 then opened, when a part immediately flew off, leaving the rest 

 so cooled by the evaporation as to remain a fluid under the atmo- 

 spheric pressure. The temperature could not have been higher 

 than — 40° in this case ; as Sir Humphry Davy has shown that 

 dry chlorine does not condense at that temperature under com- 

 mon pressure. Another tube was opened at a temperature of 

 50° ; a part of the chlorine volatilised, and cooled the tube so 

 much as to condense the atmospheric vapour on it as ice. 



A tube having the water at one end and the chlorine at the 

 other was weighed, and then cut in two ; the chlorine imme- 

 diately flew oft", and the loss being ascertained was found to be 

 1*6 grain : the water left was examined and found to contain 

 some chlorine : its weight was ascertained to be 5*4 grains. 

 These proportions, however, must not be considered as indica- 

 tive of the true composition of hydrate of chlorine ; for, from 

 the mildness of the weather during the time when these experi- 

 ments were made, it was impossible to collect the crystals of 

 hydrate, press, and transfer them, without losing much chlorine ; 

 and it is also impossible to separate the chlorine and water in 

 the tube perfectly, or keep them separate, as the atmosphere 

 within will combine with the water, and gradually reform the 

 hydrate. 



Before cutting the tube, another tube had been prepared 

 exactly like it in form and size, and a portion of water introduced 

 into it, as near as the eye could judge, of the same bulk as the 

 fluid chlorine : this water was found to weigh 1*2 grain ; a result, 

 which, if it may be trusted, would give the specific gravity of 

 fluid chlorine as 1*33 ; and from its appearance in, and on water, 

 this cannot be far wrong. 



The refractive power of fluid chlorine is rather less than that 

 of water. The pressure of its vapour at GO is nearly equal to 

 four atmospheres. 



