6g 
on thefiiioric Compounds. 
I kept SLilphuret of lead for some time in fusion in chlorine, 
the results were sulphurane (Dr. Thomson's liquor) and 
pliimbane (muriate of lead); not an atom of sulphate of lead 
was formed in the experiment, though if any oxygen had been 
present, this substance might have been expected to have been 
produced. 
I heated plumbane (muriate of lead) in sulphurous acid gas, 
and likewise in carbonic acid gas, but no change was pro- 
duced ; now, if oxygen had existed either in chlorine, or in 
its combination with lead, there is every reason to believe, 
that the attractions of the substances concerned in these ex- 
periments would have been such as to have produced the 
insoluble and fixed salts of lead, the sulphate in the first case, 
and the carbonate in the second. 
I shall not enter into any discussion upon the experiments 
in which water is said to be produced by the action of muriatic 
gas on ammonia : there is, I believe, no enlightened and can- 
did person, who has witnessed the results of processes in 
which large quantities of muriate of ammonia, made by the 
combination of the gases in close vessels, have been distilled, 
without being satisfied, that there is no more moisture pre- 
sent, than the minute quantity which is known to exist in the 
compound vapours difiused through ammoniacai and muriatic 
acid gases, which cannot be considered either as essential to 
the existence of the gases, or as chemically combined with 
them.^ 
* Dr. Henry found it very difficult to free ammonia from the aqueous vapour 
existing in it by hydrate of potassa, and probably the hydrated muriatic vapour which 
I have detected in muriatic acid gas, by a freezing mixture, is not decomposable by 
muriate of lime. 
