334 
Dr. Pearson's Experiments 
burned in the same manner as common hydrogen gaz from 
sulphuric acid, iron, and water. 
Portions of the above gazes mixed with oxygen gaz, from 
oxide of manganese, were burned in close vessels by the elec- 
tric fire, over lime-water. I could perceive no difference in 
the combustion between the gazes from the above different 
substances, nor any difference in the gaz from the same sub- 
stance at different stages of the dissolution. I did not perceive 
the lime-water to be at all disturbed in its transparency on 
my first trials ; but in subsequent ones, on viewing it more 
attentively, and in a good light, it was perceived to be very 
slightly turbid. It was equally so with all the parcels of gaz. 
To satisfy myself further, at the time I made these experi- 
ments I exploded the mixture of inflammable gaz, obtained 
by decompounding water with white hot charcoal of wood, 
with oxygen gaz; by which the lime-water was rendered quite 
milky. This inflammable gaz burnt very slowly, affording a 
deep blue lambent flame. 
To determine the quantity, and ascertain the nature, of the 
undissolved black matter in this experiment, I poured the so- 
lutions, while boiling hot, upon filtres of three folds of paper, 
and freed the filtres from the adhering solutions by pouring 
boiling water upon them. The paper was stained black by the 
solutions of wootz and steel, as far as the liquid reached, but 
the paper was only stained black at the apex of the cone of the 
filtre by the solution of iron. The quantity of black matter on 
the filtres from the two former solutions was apparemiy six or 
eight times more than from the solution of iron : but it ad- 
hered too firmly, and was in too small a quantity, to determine 
the proportion accurately by weight. I estimated the quantity 
