33 0 
Dr. Pearson's Experiments 
blast of air in the charcoal fire of the forge, emitted sparks 
like those of iron, and steel, in these circumstances. At the 
same time it melted in the state of oxide of iron. 
§ 5. Experiments with diluted Nitrous Acid. 
(а) 200 grains of the substance under examination were 
first digested, and afterwards boiled in three ounce measures 
of concentrated nitrous acid mixed with an equal bulk of 
water. A dissolution took place, with a discharge of nitrous 
gaz. The mixture, reduced by boiling to half its bulk, was 
diluted with water, and while boiling hot was filtrated through 
paper. Excepting a few grains of black matter, the whole 
mixture passed through the filtre. The filtrated liquor eva- 
porated to dryness afforded matter, which after being kept red 
hot for two hours was a light spongy reddish substance ; that 
weighed 270 grains. 
(б) 30 grains of the reddish substance (§5. a) digested in 
half an ounce of concentrated acetic acid, on filtration and eva- 
poration to dryness yielded one grain and a half of gray mat- 
ter, which was ascertained to be oxide of iron. 
(c) The blackish matter left upon the filtre (§5. a) was re- 
peatedly digested in diluted nitrous acid. The hi .rated liquors 
on evaporation afforded at first a few grains of oxide of iron, 
and at last a very minute quantity. 
( d ) 60 grains of the reddish matter (§ 5. a ) with a bit of 
sugar, were digested in diluted nitrous acid. The filtrated li- 
quid on evaporation to dryness yielded a few grains of a 
brownish substance, which after many experiments, was found 
to be oxide of iron. Of these it will be satisfactory if I men- 
