Page:Proceedings of the Royal Society of London Vol 1.djvu/493

Rh When it is kept in contact with mercury alone, it yields azote and a white powder. consisting of a mixture of calomel and corrosive sublimate.

One means of estimating the proportion of the elements was obtained 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 exhausted vessels, the tendency to explosion was such, that no estimate could be formed of its elements, from the small quantiﬁes 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 necsary 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 91 of chlorine; and since this proportion 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 estimate 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 muriatic 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 he found from which we can form a previous judgement of such combinations; and he takes occasion to remark, that other philosopha's who have presumed that azote contains oxygen, are not warranted in their inference by any laws that he has observed.

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.