1823.] On Fluid Chlorine. 85 



On Fluid Chlorine*. 

 [Read March 13, 1823.] 



IT is well known that before the year 1810 the solid substance 

 obtained by exposing chlorine, as usually procured, to a low 

 temperature, was considered as the gas itself reduced into that 

 form ; and that Sir Humphry Davy first showed it to be a 

 hydrate, the pure dry gas not being condensible even at a tem- 

 perature of 40 F. 



I took advantage of the late cold weather to procure cry- 

 stals of this substance for the purpose of analysis. The 

 results are contained in a short paper in the Quarterly Journal 

 of Science, vol. xv.f Its composition is very nearly 27*7 chlo- 

 rine, 72'3 water, or 1 proportional of chlorine and 10 of water. 



The President of the Royal Society having honoured me 

 by looking at these conclusions, suggested, that an exposure 

 of the substance to heat under pressure would probably lead 

 to interesting results ; the following experiments were com- 

 menced at his request. Some hydrate of chlorine was pre- 

 pared, and, being dried as well as could be by pressure in 

 bibulous paper, was introduced into a sealed glass tube, the 

 upper end of which was then hermetically closed. Being 

 placed in water at 60, it underwent no change ; but when put 

 into water at 100, the substance fused, the tube became filled 

 with a bright yellow atmosphere, and on examination was 

 found to contain two fluid substances : the one, about three- 

 fourths of the whole, was of a faint yellow colour, having very 

 much the appearance of water ; the remaining fourth was a 

 heavy bright yellow fluid, lying at the bottom of the former, 

 without any apparent tendency to mix with it. As the tube 

 cooled, the yellow atmosphere condensed into more of the 

 yellow fluid, which floated in a film on the pale fluid, looking 

 very like chloride of nitrogen ; and at 70 the pale portion 

 congealed, although even at 3 the yellow portion did not 

 solidify. Heated up to 100 the yellow fluid appeared to boil, 

 and again produced the bright coloured atmosphere. 



By putting the hydrate into a bent tube, afterwards herme- 

 tically sealed, I found it easy, after decomposing it by a heat 

 of 100, to distil the yellow fluid to one end of the tube, and to 



* Phil. Trans. 1823, p. 160; also Phil. Mag. Ixii. p. 413. t See page 81. 



