106 Mr. Faraday on two neiv Compounds [Aug. 



fluid, and the vessel remained full of defiant gas. Chlorine was 

 then admitted in repeated portions as before ; consequently more 

 of the fluid formed ; and ultimately a large portion was obtained 

 in the bottom of the vessel, and an atmosphere of chlorine above 

 it. It was now exposed to sun light. The chlorine immediately 

 disappeared, and the vessel became filled with muriatic acid gas. 

 Having ascertained that water did not interfere with the action 

 of the substances, a small portion was admitted into the vessel 

 which absorbed the muriatic acid gas, and then another atmo- 

 sphere of chlorine was introduced. Again exposed to the light, 

 this was partly combined with the carbon, and partly converted 

 into muriatic acid gas ; which, being as before absorbed by the 

 water, left space for more chlorine. Repeating this action, the 

 fluid gradually became thick and opaque from the formation of 

 crystals in it, which at last adhered to the sides of the glass as 

 it was turned round ; and ultimately the vessel only contained 

 chlorine with the accumulated gaseous impurities of the succes- 

 sive portions ; a strong solution of muriatic acid, coloured blue 

 from the solution of a little brass, and the solid substance. 



I have frequently carried the process thus far in retorts ; and 

 it is evident that any conveniently formed glass vessel will 

 answer the purpose. The admission of water during the process 

 prevents the necessity of repeated exhaustion by the air-pump, 

 which cannot be done without injury to the latter; but to have 

 the full advantage of this part of the process, the gases should 

 be as pure as possible, that no atmosphere foreign to the experi- 

 ment may collect in the vessel. 



In order to cleanse the substance, the remaining chlorine and 

 muriatic acid were blown out of the vessel by a pair of bellows, 

 introduced at the stoppered aperture, and the vessel afterwards 

 filled with water, to wash away the muriatic acid and other soluble 

 matters. Considerable care- is then requisite in the further 

 purification of the chloride. It retains water, muriatic acid, and 

 a substance, which I find to be a triple compound of chlorine, 

 carbon, and hydrogen, formed from the cement of the cap ; and 

 as all these contain hydrogen, a small quantity of any one 

 remaining with the chloride would, in analysis, give erroneous 

 results. Various methods of purification may be devised, 

 founded on the properties of the substance, but I have found the 

 following the most convenient. The substance is to be washed 

 from off the glass, and poured with the water into a jar ; a little 

 alcohol will remove the last portions which adhere to the glass ; 

 and this, when poured into the water, will precipitate thechlo- 

 ride, and the whole will fall to the bottom of the vessel. Then 

 having decanted the water, the chloride is to be collected on a 

 filter, and dried as much as may be by pressure between folds 

 of bibulous paper. It should next be introduced into a glass 

 tube, and sublimed by a spirit lamp : the pure substance with 

 water will rise at first, but the last portions will be partially 



