446 PROF. ROSE ON A NEW COMBINATION OF THE 
oxide of lead, I evaporated the whole to dryness, and heated the mass 
to redness. I obtained from 1°613 grammes of the compound, treated 
with fuming nitric acid and mixed with 10°739 grammes oxide of lead, 
a mass which after being heated weighed 12-238 grammes, and which 
contained therefore 1499 grammes of sulphuric acid, or 92°93 per cent. 
This experiment proves that the loss cannot be due to any formation 
of hyposulphurie acid. 
The result of experiments in which I endeavoured to oxidize the 
sulphurous acid by solutions of gold were much more uncertain. 
For this purpose I employed a carefully prepared solution of the triple 
salt, the chloride of gold, and sodium. The compound was brought 
into contact with this in the same manner as in the former experi- 
ments with nitric acid. The mixture was submitted, out of contact 
with the air, to a moderate heat for about twenty-four hours. Two 
experiments, conducted with equal care, gave however such widely 
differing results, that it was impossible for me to explain the cause of 
the great dissimilarity : for from 1259 grammes of the compound I ob- 
tained in one experiment only 0°058 of a gramme of metallic gold; 
whilst in a second experiment I obtained, from a much smaller quan- 
tity of the compound, out of 0°667 of a gramme, more gold, namely 
0°196 of a gramme. 
The estimating of the sulphuric acid in the compound gave much 
more satisfactory results; I was obliged to be contented with these, and 
to estimate the quantity of sulphurous acid by the loss sustained. The 
determination was effected in the following manner: a quantity of the 
compound, weighed in a small glass bottle with a stopper, was put into 
a larger bottle, which could also be closed by a glass stopper: this 
contained a solution of chloride of barium, to which free muriatic acid 
was added. As soon as the little bottle was introduced, the larger one 
was closed; and by shaking the vessel, the stopper of the little bottle, 
which was merely loosely fixed, was thrown off, so that the compound 
might mix with the solution of chloride of barium ;—an exceedingly 
violent but not dangerous action ensued. 
After the sulphate of baryta was deposited, the liquid was quickly 
filtered out of contact with the air, and its weight determined. An 
addition of muriatic acid to the solution of chloride of barium is quite 
necessary, because otherwise the sulphate of baryta cannot easily be 
filtered, but passes milky through the filter. 
I have analysed four different portions, prepared at different times, in 
this manner, and have obtained results which, though they agree much 
less than those of less easily decomposable substances, yet on account 
of the great decomposability and volatility of the compound, and there- 
fore the difficulty of freeing it from uncombined sulphuric or sulphur- 
ous acid, agree more nearly than I expected. 
