REPORT ON CHEMISTRY. 
4G5 
-f* 2 (Cl + H -f- P + 3 H), the latter member of which repre¬ 
sents the composition of the muriate of phosphuretted hydro¬ 
gen- 
The interest connected with these compounds arises from 
the analogy in constitution between ammonia and phosphuretted 
hydrogen and their corresponding salts. The hydriodate and 
the hydrobromate of phosphuretted hydrogen, the similar salts 
of ammonia, as well as sal ammoniac, all crystallize in cubes, and 
are all compounds of the same character, in which a gaseous acid 
containing one atom of hydrogen is combined with a gaseous base 
containing three atoms of hydrogen. Whatever opinion, there¬ 
fore, we form of the constitution of sal ammoniac, the same, it is 
obvious, must be entertained of the compounds above described. 
The similarity in properties and the identity in form of sal 
ammoniac with the chlorides of the alkalifiable metals, formerly 
induced some eminent chemists to consider it as a similar com¬ 
pound of chlorine with a metal. This opinion was very much 
strengthened by the remarkable property of sal ammoniac in 
forming an amalgam with mercury when placed in the circuit of 
a galvanic battery. But if instead of comparing this salt of am¬ 
monia with those of potassium and sodium, we compare it with 
that of phosphuretted hydrogen, the atomic constitution of which 
is precisely analogous, we shall no longer see the necessity of re¬ 
sorting to the supposition of a compound volatile metal (N + 4H). 
Ammonia as a volatile compound base no longer stands alone, 
and as we cannot suppose the existence of any metal P + 4H, 
so all probability of any such as N +4 H is done away. 
The very interesting inquiry into the relations of these com¬ 
pounds of phosphuretted hydrogen to mercury in the galvanic 
circuit was not made by Serullas. It remains for other experi¬ 
menters who yet survive to follow up the many discoveries made 
by this indefatigable chemist during the few brilliant years he 
had devoted himself to his favourite science. 
Oxides of chlorine and iodine .—Much has of late years been 
added to our knowledge of the compounds of chlorine and 
iodine with oxygen and with each other. Great obscurity, 
however, as will appear from what has been already stated re¬ 
garding euclilorine and chlorous acid, still rests on the lower 
degrees of oxidation of these two substances. From the experi¬ 
ments of Sementini—who, by passing a mixture of iodine vapour 
and oxygen through a red-hot tube, obtained an oily, amber-like 
liquid, which decomposes combustible substances and inflames 
phosphorus and potassium,—it would appear that there exists 
one or more compounds of iodine with less oxygen than in iodic 
acid; but nothing definite is yet known on the subject, 
2 G 
