The workingman's advocate. [volume] (Chicago [Ill.]) 1864-1877, 1871-03-04

I 1hls substance is now in solution in til,
water and in order to obtain it in soliC
iorm, the water has to be driven off b,
neat. Clarifying the solution and eyapc
rating the water slowly, We obtain the cleal
vltreous, or glass like salt II is then crys
tallzed. and in this act solidi6es a lary.
amount OF water with it. If crystallizec
at low temperature, every 78 parts of tEt
IRON sulphate will solidify 7x9, or 63 part,
ot water if crystallized at 176 degree.
ahr', 1t will Onl y solidify 4x9, or 36 part.
2! water, while it will take 5x9 or 50 parts,
4 tnere Is an excess of sulphuric acid in
tne solution. Such water soliditied in a
crystal Is called water Of erystallixation.
by heating the iron sulphate, most of this
water Is easily driven of, except the last
nlne parts, which require heat of 572
degrees Fair. to expel them; then the salt
loses lts former appearance entirely, and is
changed INTO q white powder, called anhy-
ufous iron suiphate-anhydrous signifying
free fron water.
: y hen this white powder is heated to 6I7
degrees, the boiling-point Of sulphuric acid.
tnls Is driven cf and may be collected by
means or the proper arrangements, which
we do not, however, advise young chem
lcal student to try. The sulphuric acid OBJ
tanned In this way from the dstiIlation Of
the so-called vitriol, being Of an oily ma
ture' 1t was very natural that the old chem
lists called it oil of vitriol before its true
composition was known. 1t contains less
water, and ls therefore much stronger than
TIE common, so-called English, sulDhuric
acid. 1t is now called Nordhausen yitriol
after the town of that name, situated on
the edge Of the Hartz mountains in Ger
many It is generally supposed that the
acid was manufactured there, but this idea
is probably erroneous Nordhausen was
simply the great business centre of that
part Of the country, and merchants ordered
their supplies from that place. though the
acid was made from the ores Of tke Ramels.
berg. 1t is also CALLED fnming sulphuric
acid, because it gives off strong fumes
when the bottle is opened
The remnant left. after the operation Of
heating the iron sulphate to GIT degrees or
higher, is Of course the oxide Of iron. 1t is
red powder. used as an oil paint, and 50
tlne and sharp that it Is very valuable for
silver and glass. 1t was called
cOtcOthdr, or capm mOrtuum, meaning
de0d head, from the fact that it is vitriol
burned to death, as the old chemists sup
posed.
The green vitriol as found in the trade,
Is, however, seldom made from old iron,
water, and sui phuric acid, because nature
gives compound from which it may be
made at cheaper rate. This compound
iron Pyrltes, or fools gold-so called be-
cause Ignorant foolish people all over the
V orld are continually bringing pieces of
this substance TO chemists, metallurgists,
for jewellers, wanting to sell it for gold, as
i looks somewhat like it. Usually they
will not believe the truth when told what It
is. It IS a compound of iron and sulphur,
and has no value as an ore Of iron, as it
would cost too much to get the iron ont
Rheh besides would be of very inferior
quality therefore it is roasted, by which
operation the iron and the sulphur are oxy-
iized, a great portion Of the sulphur is lost
rs gaseous sulphuric acid. another portion
changes into sulphuric acid, which combines
With the oxide of iron, and thus forms the
ron sui phate, which is dissolved out of the
mass by water, and the solution clarified,
sVapOrated, and the salt crystallized.