4-73 



When it is kept in contact with mercury alone, it yields azote and 

 a white powder, consisting of a mixture of calomel and corrosive sub- 

 limate. 



One means of estimating the proportion of the elements was ob- 

 tained from this mode of analysis, and it appeared to be 19 azote to 

 81 chlorine. 



In such attempts as were made to decompose this substance in ex- 

 hausted vessels, the tendency to explosion was such, that no estimate 

 could be formed of its elements, from the small quantities on which 

 it was safe to operate. 



The mode of analysis on which the author places the most reliance, 

 is that performed by means of muriatic acid. According to his view 

 of the play of affinities in this process, ammonia is formed by the 

 union of the azote in the compound with the hydrogen of one part 

 of the muriatic acid, occasioning the chlorine of both to be set free ; 

 while the ammonia so formed combines with another portion of the 

 muriatic acid, and is found in the solution as muriate of ammonia. 

 In addition to the quantity of chlorine actually evolved in this mode 

 of trial, it was necessary to estimate the quantity remaining dissolved 

 in the liquid. For this purpose the sulphuric solution of indigo was 

 employed, and the quantity of chlorine estimated by the quantity of 

 blue colour destroyed. 



From the results of two experiments, the author infers that nine 

 grains of azote are combined with 9 1 of chlorine ; and since this pro- 

 portion accords very nearly with the supposition of one volume of 

 azote with four equal volumes of chlorine, he regards the present as 

 a satisfactory instance of the law of definite proportions; for the esti- 

 mate obtained by the action of mercury upon the oil, differs no more 

 than might be expected from the nature of the experiment. 



Since one of azote combines with three of hydrogen to form am- 

 monia, and three of hydrogen combine with three of chlorine in mu- 

 riatic acid, the author had thought it probable that one of azote would 

 have been found combined with three of chlorine, but is now of opinion 

 that no strict laws of analogy are to be found from which we can 

 form a previous judgement of such combinations ; and he takes oc- 

 casion to remark, that other philosophers who have presumed that 

 azote contains oxygen, are not warranted in their inference by any 

 laws that he has observed. 



Experiments on the Production of Cold by the Evaporation of the Sul- 

 phuret of Carbon. By Alexander Marcet, M.D. F.R.S. one of the 

 Physicians to Guy's Hospital. Read July 8, 1813. [Phil. Trans. 

 1813, p. 252.] 



In a former paper which the author communicated jointly with 

 Professor Berzelius on sulphuret of carbon, its remarkable volatility 

 was noticed ; and as it appeared likely on that account to produce a 

 great degree of cold by evaporation, Dr. Marcet has been induced to 

 make a course of experiments on that subject. 



