VOLATILE CHLORIDES WITH AMMONIA. 43 
verse crystalline forms. They appeared homogeneous, although 
their form could not be determined. I expected to obtain cry- 
stals of parasulphat-ammon ; but even these were not evident at 
any period of the evaporation. The evaporated mass remained 
for a long time moist and smeary, but at last dried perfectly. It 
was left in vacuo till it no longer decreased in weight. 
1-227 gramme of the dried mass, examined in the manner 
above mentioned, gave 1136 gramme chloride of silver, and 1-794 
gramme sulphate of barytes. This corresponds to 22°84 per cent. 
chlorine, and 20°17 per cent. sulphur in the compound. 
The compound dissolved in water and evaporated, was com- 
posed just as the mass originally prepared. It has, on its solution 
in water, taken up none of it. 
From these researches it results, that the ammoniacal com- 
pound is not a mixture of several substances, but a combination 
of a peculiar kind. But if this is the case, its constitution leads 
to some considerations not quite unimportant. 
According to Walter and Persoz, the volatile compounds which 
have recently been discovered, of acids, with chlorides analo- 
gously constituted, are considered as acids in which a portion of 
the oxygen is replaced by chlorine. This supposition, which 
has its origin in the theory of substitutions, has at first sight 
much in favour of it, and is recommended by its simplicity ; for 
although oxygen, with respect to its properties, stands pretty 
much isolated, yet it has of all elements, on the one hand, the 
most similarity to sulphur, on the other, to chlorine or fluorine. 
It would, therefore, it is true, be a highly interesting, although 
to many chemists perhaps not quite unexpected fact, if an iso- 
morphous compound were to be discovered, in which an equiva- 
lent of chlorine holds the place of oxygen. 
Thisview, however, on closer consideration, loses in probability. 
If we compare the combinations which oxygen and chlorine form 
with hydrogen in their gaseous state, we find that they possess 
quite different relations of condensation. The relations of con- 
densation of gaseous compounds which contain elements that 
can hold each other’s place in other solid combinations, and which 
are isomorphous, are on the contrary always the same. This 
is the case in the combinations of chlorine, bromine and iodine 
with hydrogen, as well as in those of phosphorus and arsenic with 
the same element. 
Berzelius likewise speaks decidedly, from other considerations, 
