The decomposition in this process is very simple, and must be supposed to depend merely upon the attraction of the mercury for chlorine, in consequence of which the azote is set free; and if the result does not strictly demonstrate the proportions of chlorine and azote in the compound, yet it seems at least to shew, that these are its only constituents.

As muriate of ammonia and chlorine are the only products resulting from its action upon solution of muriatic acid, it seems reasonable to infer, that this action depends on a decomposition of part of the muriatic acid, by the attraction of the new compound for hydrogen to form ammonia, which, at the moment of its production, combines with another portion of the acid, the chlorine of both compounds being set free.

On this view, the quantity of chlorine formed from a certain quantity of the compound being known, it becomes easy to determine the composition of the compound; for, ammonia being formed of three volumes of hydrogen and one of azote, and muriatic acid of one volume of hydrogen and one of chlorine, it is evident, that for every three volumes of chlorine evolved by the decomposition of muriatic acid, one volume of azote must be detached from the compound; and the weight of chlorine in the compound must be less than the weight of the whole quantity of chlorine produced by a portion, which is to the azote in the compound as 295 to 2295, if the relative specific gravities of the two gases be considered as 2,627 and 1.

Two grains of the compound, when exposed at the temperature of 62° FAHRENHEIT, and under a pressure of the atmosphere equal to that of 30,1 inches of mercury to strong solution of muriatic acid in a proper apparatus, afforded 3,91 cubic inches of chlorine.

In another experiment, one grain of the compound afforded 1,625 cubic inches of chlorine.

In a third experiment, one grain produced only 1,52 cubic inches.

In the two last experiments the compound was acted upon much more slowly, and the gas generated exposed to a much larger surface of solution of muriatic acid, and the appearance of a smaller relative proportion of chlorine must be ascribed to the absorption of a larger proportion of that gas by the liquid acid; and I found by exposing concentrated solution of muriatic acid to chlorine, that it soon absorbed nearly its volume of that gas.

I attempted to remove the source of error in the experiment, by using liquid muriatic acid holding chlorine in solution; but in this case the quickness of the action of the compound on the acid was greatly diminished, and it not being easy to obtain the point of absolute saturation of the acid with chlorine, some of the gas was absorbed in the nascent state during its slow production; and in most of my experiments made in this manner, I obtained less chlorine from a given weight of the compound, than in operating on pure solution of muriatic acid.

Liquid muriatic acid, whether concentrated or diluted in its pure state, does not affect the colour of the sulphuric solution of indigo; but it is immediately destroyed by solutions containing chlorine dissolved in them. The quantity of solution of indigo, which is deprived of colour by a given quantity of solution of chlorine, is directly as the proportion of chlorine it contains; and I found that the same quantity of chlorine, whether dissolved in a large or a small quantity of solution of

muriatic acid, destroyed the colour of the same quantity of the blue liquor.

On this circumstance it was easy to found a method of determining the precise quantity of chlorine produced in solution of muriatic acid, from a given quantity of the compound; namely, by comparing the power of a given quantity of muriatic acid, containing a known quantity of chlorine, to destroy the colour of solutions of indigo, with that of the muriatic acid, in which the compound had produced chlorine.

Two experiments were made. In the first, a grain of the compound was exposed on a large surface beneath a tube inverted in about six cubic inches of solution of muriatic acid, and the chlorine absorbed by agitation as it was formed. The acid so treated destroyed the colour of seven cubic inches of a diluted sulphuric solution of indigo; and it was found, by several comparative trials, that exactly the same effect was produced in another equal portion of the same solution of indigo, by 2,2 cubic inches of chlorine dissolved in the same quantity of muriatic acid.

In the second experiment, 1,3 cubic inches of chlorine were evolved in the gaseous form, the thermometer being at 58°, and barometer at 30,33, and suffered to pass into the atmosphere; and by the test of the solution of indigo, it was found that ,75 of a cubic inch remained dissolved in the acid.

Now, if the mean of these two experiments be taken, it appears that 1,61 grains of chlorine are produced in solution of muriatic acid by the action of a grain of the compound; and calculating on the data just now referred to, the compound must consist of 91 of chlorine and 9 of azote in weight, which

in volume will be nearly 119 to 30; and this estimation differs as little as might be expected from that gained by the action of mercury upon the compound.

It may fairly be concluded, that M. GAY LUSSAC's principle of the combination of gaseous bodies, in definite volumes, strictly applies to this compound, and that it really consists of four volumes of chlorine to one of azote; and the volumes likewise exactly coincide with the laws of definite proportions; and the detonating compound may be regarded as composed of one proportion of azote 26, and four proportions of chlorine 261.

I attempted a comparative experiment on the proportions in the compound, by estimating the quantity of azote produced in the decomposition of ammonia by it; but I found that this process was of no value for the purpose of analysis, for water. appeared to be decomposed at the same time with the ammonia, and nitric acid formed; and, in consequence, the quantity of azote evolved was much less than it would have been, supposing the ammonia decomposed by the mere attraction of chlorine for hydrogen.

The results of the analysis of the new compound are interesting for several reasons.

They shew, what seemed probable from other facts, that there is no strict law of analogy, which regulates the combinations of the same substance with different substances. As three of hydrogen combine with one of azote, and one of hydrogen with one of chlorine, I thought it probable that the new compound would contain three of chlorine to one of azote, which is not the case.

This compound is the first instance known of one proportion

of a substance uniting to four proportions of another substance, without some intermediate compound of 1 and 1, 1 and 2, and 1 and 3; and the fact should render us cautious in adopting hypothetical views of the composition of bodies from the relations of the quantities in which they combine. Those who argue that there must be one proportion of oxygen in azote, because there ought to be six proportions in nitric acid, instead of five, which are produced from it by analysis, might with full as much propriety contend, that there must be azote in chlorine in some simple multiple of that existing in the compound.

It may be useful to shew, that many hypotheses may be framed upon the same principles; and which, consequently, must be equally uncertain. Views of this nature may be important in directing the practical chemist in his researches ; but the philosopher should carefully avoid the developement of them with confidence, and the confounding them with prac tical results.

The compound of chlorine and azote agrees with the compounds of the same substance with sulphur, phosphorus, and the metals, in being a non-conductor of electricity; and these compounds are likewise decomposable by heat, though they require that of Voltaic electricity.

Sulphur combines only in one proportion with chlorine; and hence the action of Sulphurane, or Dr. THOMSON's muriatic liquor upon water, like that of the new compound, is not a simple phenomenon of double decomposition.

It seems proper to designate this new body by some name: Azotane is the term that would be applied to it, according to my ideas of its analogy to the other bodies which contain chlorine; but I am not desirous, in the present imperfect and