The true northerner. [volume] (Paw Paw, Mich.) 1855-1920, 1885-07-02
MECHANICAL.


M. FoRDoz gives in Cosmos very
simple and useful method for detecting
lead i'll the timing of culinary utensils.
The vessel being carefully cleaned to
remove grease, drop of nitric acid is
applied to any part, and gentle heat
is used to dry the spot. A drop of So
luton of iodide of potassium is applied
to the spot, and if lead be present
yellow iodide of lead is formed.
THE following simple method for the
consumption of smoke is given by Ger
and let it burn until the Goals are in q
bright glow; then rake the Goals on the
CRATE to the right and left, SO as to form
an empty space along the middle, and
put the fresh Goals into this space. The
smoke which is formed from the fresh
Goals is consumed by the glowing fires
on either side. LII tue CRATE is very wide
two such open spaces in the fire are adj
vantageous for the addition of fresh
fuel.
The bone industry of the country Is
an important one. The four feet of an
ordinary OK will make pint of heats
foot oil. Not q bone of any animal is
thrown away. Many cattle shin bones
are shipped to Europe for the making
of knife handles, where they bring $40
per ton. The thigh bones are the most
valuable, being worth $50 per ton for
cutting into toothbrush handles. The
foreleg bones are worth $50 per ton,
and are made into collar buttons, para
sol handles, and jewelry, though sleeps
legs are the staple for parasol handles.
The water in which the bones are boiled
is reduced to glue, the dust which
comes from saving the. bones is fed to
cattle and poultry, and all bones that
cannot be used as noted, or for bone
black, used in refining the sugar we
eat, are made into fertilizers, and help
enrich the soil.
SIR FREDERICK BRAMwELL, President
of the English Institute of Civil Engi-
neering, declares that for the large
steel forgings required In the present
day for engine shafts and for cannon,
the operations of light steam hammers
are positively hurtful, tending to pro-
duce internal flaws, and that the blows
OF even the heaviest hammers are less
efiicacious than pressure applied with
out blow. He thinks the time is not
far distant when all steel in it's molten
state will be subjected TO pressure with
the object of diminishing the size of any
cavities containing imprisoned gases, or
else that the same result will be OBJ
tanned by other mechanical means, the
possible nature OF which he does not
specify, but by which a casting may be
obtained free from all blow holes, so
that, when. afterward forged by press
ure, and not by percussion, it may be
trusted to contain no local defect.
SOME improvements in the construc-
ton OF house chimneys have from time
to time been suggested, and it is claim
ed that the best result is reached by
inclosing hard-baked glazed pipe in a
thin wall of bricks, such chimneys not
only drawing better than those made in
the usual way, but there is also less
danger from defective fues." 1t Is ar
gucd that to build chimneys with double
or s-inch walls makes them very large,
more expensive, and yet not so good as
when they contain the smooth, round
fiues. To leave an air chamber between
them, for vcntilating, is pronounced
better than to open directly into the
smoke hue, because il will not impair
the draught for the fire, and there will
be no danger of sooty odor in the
room when the circulation happens To
lead downward. The outside chimney,
If any, should have an extra air cham.
Der between the very outer wall and
the hack of the fireplace, to save heat.