1821.] of Chlorine and Carbon, &c. Ill 



lead of the glass tube. • An evident action had taken place, and 

 the oxygen evolved, meeting with the liberated carbon, would 

 produce the carbonic oxide. This experiment has been repeated 

 several times with the same results. 



When the perchloride of carbon is heated with metallic 

 oxides, different results are produced according to the propor- 

 tions of oxygen in the oxides. The peroxides, as of mercury, 

 copper, lead, and tin, produce chlorides of those metals, and 

 carbonic acid ; and the protoxides, as those of zinc, lead, &c. 

 produce also chlorides ; but the gaseous products are mixtures 

 of carbonic acid and carbonic oxide. 1 have frequently per- 

 ceived the smell of phosgene gas on passing the chloride over 

 oxide of zinc ; and as the substance easily liberates chlorine at 

 high temperatures, it will be readily seen how a small portion of 

 that gas may be formed. It also happens, sometimes, that 

 the protoxides become blackened from the deposition of 

 charcoal. 



When the vapour of the chloride is passed over lime, baryta, 

 or strontia, heated red hot, a very vivid combustion is produced. 

 The oxygen and the chlorine change places, and both the metals 

 and the carbon are burnt. Chlorides are produced, carbonic 

 acid is formed and absorbed by the undecomposed parts of the 

 earths, and carbon is deposited. In these experiments no car- 

 bonic oxide is produced. When passed over magnesia, there is 

 no action on the earth, but the perchloride of carbon is con- 

 verted by the heat into protochloride. 



In these experiments with the oxides no trace of water could 

 be perceived. 



Having thus far described the properties of the substance, I 

 shall now gi^e the reasons which induce me to consider it a 

 true chloride of carbon, and shall endeavour to assign its com- 

 position. My first object was to ascertain whether hydrogen 

 existed in it or not. When phosphorus is heated in it, a small 

 quantity of muriatic acid is generally formed ; but doubt arises 

 as to the cause of its production, from the circumstance that the 

 phosphorus, as already mentioned, may be the source of the 

 hydrogen. When potassium is heated in the vapour of the sub- 

 stance, there is generally a small expansion of volume, and 

 inflammable gas produced ; but it is very difficult to cleanse 

 potassium both from naptha and an adhering crust of moist 

 potash ; and either of these, though in extremely minute quan r 

 tities, would give fallacious results. 



A more unexceptionable experiment made with iron has been 

 already described ; and the inferences from it are against the 

 presence of hydrogen in the compound. 



Some of the substance in vapour was electrized over mercury 

 by having many hundred sparks passed through it. Calomel 

 was formed, and carbon deposited. A very minute bubble of 



