192 CLASSICS OF MODERN SCIENCE 

 impurity of the hydrate used. When that end of the tube in which 

 the yellow fluid lay was broken under a jar of water, there was an 

 immediate production of chlorine gas. 



I at first thought that muriatic acid and euchlorine had been 

 formed ; then, that two new hydrates of chlorine had been produced ; 

 but at last I suspected that the chlorine had been entirely separated 

 from the water by the heat and condensed into a dry fluid by the 

 mere pressure of its own abundant vapour. If that were true, it fol- 

 lowed, that chlorine gas, when compressed, should be condensed into 

 the same fluid, and, as the atmosphere in the tube in which the fluid 

 lay was not very yellow at 50° or 60°, it seemed probable that the 

 pressure required was not beyond what could readily be obtained by a 

 condensing syringe. A long tube was therefore furnished with a cap 

 and stop-cock, then exhausted of air and filled with chlorine, and be- 

 ing held vertically with the syringe upwards, air was forced in, which 

 thrust the chlorine to the bottom of the tube, and gave a pressure of 

 about 4 atmospheres. Being now cooled, there was an immediate de- 

 posit in films, which appeared to be hydrate, formed by water con- 

 tained in the gas and vessels, but some of the yellow fluid was also 

 produced. As this however might also contain a portion of the water 

 present, a perfectly dry tub and apparatus were taken, and the chlorine 

 left for some time over a bath of sulphuric acid before it was intro- 

 duced. Upon throwing in air and giving pressure, there was now no 

 soHd film formed, but the clear yellow fluid was deposited, and more 

 abundantly still upon cooling. After remaining some time it disap- 

 peared, 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 proper- 

 ties, as well as I could when obtained by heat from the hydrate. 

 However obtained, it always appears very limpid and fluid, and exces- 

 sively volatile at common pressure. A portion was cooled in its tube 

 to 0° ; it remained fluid. The tube was then opened, when a part im- 

 mediately flew off, leaving the rest so cooled by the evaporation as to 

 remain a fluid under the atmospheric pressure. The temperature 

 could not have been higher than 40° in this case; as Sir Humphrey 

 Davy has shown that dry chlorine does not condense at that tempera- 

 ture under common pressure. Another tube was opened at a tem- 



