MICHAEL FARADAY 191 



substance for the purpose of analysis. The results are contained in a 

 short paper in the Quarterly Journal of Science, Vol. XV. Its com- 

 position is very nearly 27.7 chlorine, 72.3 water, or i 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 commenced at his request. Some hydrate 

 of chlorine was prepared, and being dried as well as could be by pres- 

 sure 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 sub- 

 stances : the one, about three-fourths of the whole, was of a faint yel- 

 low 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 32° 

 the yellow portion did not solidify. Heated up to 100° the yellow 

 fluid appeared to boil, and again produced the bright coloured atmos- 

 phere. 



By putting the hydrate into a bent tube, afterwards hermetically 

 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 so separate it from the re- 

 maining portion. In this way a more complete decomposition of the 

 hydrate was effected, and, when the whole was allowed to cool, neither 

 of the fluids solidified at temperatures above 34°, and the yellow por- 

 tion not even at 0°. When the two were mixed together they grad- 

 ually combined at temperatures below 60°, and formed the same solid 

 substance as that first introduced. If, when the fluids were separated, 

 the tube was cut in the middle, the parts flew asunder as if with an 

 explosion, the whole of the yellow portion disappeared, and there was 

 a powerful atmosphere of chlorine produced ; the pale portion on the 

 contrary remained, and when examined, proved to be a weak solution 

 of chlorine in water, with a little muriatic acid, probably from the 



