47 
Cast Iron, Steel, and Malleable Iron, 
those specimens, in three different glasses, hydrochloric acid. 
No. 1. was attacked very violently: the liquid became milky, 
and a yellow precipitate with a very few traces of black flocks 
remained. During a space of nine weeks the solution had im- 
bibed so much water from the surrounding atmosphere, that 
the glasses were nearly overflowing. The acid was then 
poured off and distilled water poured over the precipitate ; the 
precipitate was now white and flocky, and the most copious 
of the three samples. 
No. 2. was not so violently attacked, and did not become 
milky: first, fine black scales became separated, adhering to 
the sides of the glass very regularly; afterwards, the interstices 
between these black scales or spots became filled up with the 
before-mentioned yellow powder. The whitish powder ap- 
peared very fine, never granulated or flocky, and adhered to 
the sides of the glass almost entirely. The whitish precipitate 
of Nos. 1. and 3. fell to the bottom of the glass. 
No. 3. was the most rapidly attacked by the acid, and 
became milk}q the same as No. 1. The liquid was, after a 
lapse of nine weeks, rather turbid and showed the smallest 
quantity of black scales swimming in the liquid. A few hours 
after the acid had been poured over it, it became turbid and 
very yellow, which showed that it had combined the quickest 
with the oxygen of the atmosphere. 
The day after the acid had been poured on No. 2. the sur- 
face only began to acquire a yellow colour. In No. 3. the 
l)lack flocks seemed entirely to have disappeared, and the yel- 
lowish powder ascended in part to the surface, and the remain- 
der fell to the bottom. The difference therefore between the 
granulated exterior of the same bar, and the interior crystal- 
lization, seems to consist in this, that the exterior produces less 
white powder in a very divided state and more carbonaceous 
scales, or that the granulated parts, be they inside or outside 
of the bar, contain less of the white powder and more black 
scales than the crystallized ; I therefore infer, that the carbon 
is here substituted for silicon ; and as No. 3. contained more 
silicon than No. 2., it seems either that the silicon of No. 2. 
was partially driven away during its preparation by the carbon, 
or rather that the silicon remained in combination with carbon, 
A fragment of Bombay wootz was also very slowly attack- 
ed by the acids, and deposited on the sides of the glass the 
before-mentioned white powder. 
21*71 grains of No. 3. left white residuum dried at the heat 
of boiling water = 0*3437 grains. 
A part of a coloured blister of Dannemora steel deposited 
likewise a *ix>hite iwixder, and was like the before-mentioned 
samples. 
