The true northerner. [volume] (Paw Paw, Mich.) 1855-1920, 1885-12-31
Cast Versus Wrought Iron.

NaNs WI oo' ~ htOhs
Some time ago prominent iron man
facturer, whose headquarters are in
this city, received a letter from the
Franklin Scientific Institute of Phila-
delphia, requesting such information
as might be derived from his expert
ence touching the relative capacities of
cast and wrought iron for the transmits
sion of heat. Being the maker of q
steam-heating apparatus, among other
things, he was naturally interested in
the subject. and set about making the
investigation which this inquiry sug
gested in good earnest. He commenced
series of carefully conducted expert
ments, with similar water vessels of
equal capacity and thickness, made of
the two different materials and exposed
for certain length of time to the same
degree of heat. The results, ascer-
tanned by thermometrical measurement,
were carefully noted and sent to the
Franklin Institute. In every instance
they showed large difference more
than ten per cent. in favor of cast iron
over wrought as conductor of heat ;
the conclusion being, of course, that
all apparatus designed for heating and
cooking purposes should be construct
ed of the former material, with view
to securing the quickest and best re-
suits, with the most economical con-
sumption of fuel.
The correspondence relating to these
experiments, we believe, has never
been published, and the facts devel-
oped by it are mostly the property of
IL - e
tical manufacturers and the great con-
Stunning public who are most affected
by them. The theory advanced by the
gentlemen who made these experiments
is that wrought or maileable iron,
which is relatively pure metal, has a
laminated structure, and that its fat
tening particle, lying side by side, af
ter being rolled or hammered, present
strong resistance to the action of
heat, and hence that articles made of
it are relatively poor conductors and
slow to absorb and radiate caloric, if
we may use an obsolete but very ex-
pressive and convenient scientific term.
On the other hand, he argues that
cast iron, which is not pure metal,
but, like plumbago and steel, COM
DOuuu vi llOH anu DCu lCdI VI
from, has no such fibrous or impervi-
Gus structure; but, being a brittle,
granular, porous and penetrable sub
stance, readily absorbs heat and as
readily gives it out again TO surround
ing objects by radiation or conduction.
The rougher the surface of the iron the
greater is its radiating power, and
hence highly polished parlor stoves and
steam heaters are less effective than
those which present natural surface,
or are kept tidy with coating of black
| lead
Tho only advantage in making heat
ers or cooking utensils of wrought iron
consists in the fact that thinner and
! lighter plates may be used without i'm
| pairing the strength and durability of
the articles. The Russia sheet-iron
stove, lined with fire brick, is toler
ably good heater for the parlor and sit
! ting room, because it is thin and has a
large radiating surface; but small,
cast-iron cylinder, of less than quarter
of the size, though an unsightly object,
will do more real service. Besides, the
wrought iron of the former becomes
rapidly oxidized and rusted out. Cast
iron plates, of course, would not do for
steam boiler, because, in the first
place, unless made very thick and
clumsy, they would not have the requi-
site strength and tenacity to resist the
inside pressure, and, in the second
place, they would not keep the heat in
the water, but would throw it out to
the external air by their rapid conduc-
ton. In such cases wrought iron is
the right thing in the right place; but
in many other cases where it is still
USED cast iron or cast steel might be
profitably substituted for it.
The latter has another very important
advantage in its less liability to oxidize
or rust from exposure to heat, moisture
or atmospheric air; and this is some
thing which should always be taken in
to account by manufacturers and users
of building materials, tools and ma
chinery. A thin piece of wrought iron,
such as a barrel hoop. will be entirely
eaten up with rust if left in a damp at
mosphere for any length of time, while
piece of cast iron, at the worst, will
only collect very thin and easily re-
moved surface of oxidized particles. 1t
is a well-known fact that cast steel,
which is similar in composition, is very
slow to rust, and that plumbago, which
comes nearest to cast iron, will not rust
at all. The carbon or charcoal which
is one of their constituents, although it
will combine with oxygen and burn
readily when subjected to n strong
heat, yet at ordinary temperature is
one oil the most indestructible OF all
substances, and hence is used for pen
ellis or electrodes in producing the
electric light.-Boston CultjUaf0r.
MERCURY was formerly credited with
direct action upon the liver, and was
regarded as the only relief for bilious.
ness, liver torpor, excess of bile, jaun-
dice, etc. Now we find listed as
cholago CUES liver st mulants number
of medicines of vegetable origin, viz.
podophyllin, euonymin, sanguinarla,
irisin, leptandrrn, baptism, hydrastin,
iuQlandin, and taraxacum. -ErchdnQe