169 
presents a still stronger reason for not considering hydrogen 
the reducing agent of sulphurous acid. In treating sulphur- 
ous acid with zine and hydrochloric acid in the cold, until 
the reaction ceased, freeing the sulphur from the liquid in 
the way indicated, and adding to it more hydrochloric acid 
and heating, a precipitate of sulphur was obtained indi- 
eative of the presence of a polysulphur acid; but as no 
sulphuric acid could be found in the fluid, this must have 
been hyposulphurous acid. In order to succeed in this 
experiment, much sulphurous and little hydrochloric acid 
must be taken; the separated sulphur there being also yellow. 
As therefore nascent hydrogen was without action upon 
sulphurous acid, but hyposulphurous acid and sulphur were 
separated, the probability is that sulphuretted hydrogen gas 
is formed by the direct combination of sulphur with hydro- 
gen. In the moment of separation of both hydrogen as well 
as. sulphur, we obtain all hydrogen and all sulphur as 
sulphuretted hydrogen; so in the case of treating sulphide 
of soda with an acid. 
Fe + HCl= FeCl + H 
FeS + HCl= FeCl + HS 
Fe + HSO, = FeSO, + H 
FeS + HSO, = FeSo, + HS 
But even one of these two elements, while in the nascent 
state, will combine with the other. We know that nascent 
hydrogen will combine directly with phosphorus, forming 
phosphoretted hydrogen; and, though sulphur, presenting 
so many strange and peculiar anomalies in its different 
states, may not unite as flowers of sulphur with hydrogen, 
itis very likely that sulphur, just separated from the 
decomposing hyposulphurous acid, will form sulphuretted 
gas, with nascent hydrogen. The sulphur certainly must 
have retained in this case some active principle, as it will 
directly combine upon shaking with metallic copper, and, 
as we shall see hereafter, readily with metallic cadmium. 
Besides, sulphuretted hydrogen gas is only perceived in 
this reaction after sulphur has commenced to separate. 
Cadmium and Sulphurous Acid.—In treating a piece of 
