Mower County transcript. [volume] (Lansing, Minn.) 1868-1915, 1873-09-11
Iron EiectrOtyDeS.


process of electrotying in iron: O,
leaving the bath, the iron is as hard a.
tempered steel, and very brittle. Re,
heated to dull red heat, it loses mucl
Of its sharpness and hardness. Heated
to cherry red, it becomes ,nalleable,
and may be engraved as easily as sof
steel. If the deposits are produced il
good condition, and annealed uniform
~ and with the necessary prec autiol g.
they are subject to neither warp mol
bend. There is no contraction, but,
on the contrary, slight degree of ex-
panslon, almost imperceptlble, how.
ever. Owing to the necessity of having
bank note and similar plates identical
in every respect, it is OF the first i'm
portance that they should not be dis
torted, nor have their dimensions
altered in the process of annealing. II
appears that the galvanic deposit OF
iron has not only permanent magnet
ism, but that, like soft iron. it receives
the magnetism of position. OF the
importance of the practical application
of the process there can he no doubt
whatever. BY replacing plates of cop.
per by those of iron, greater facilities
will be afforded for producing publica-
tions, works of art, and especially bank
notes and checks. Iron electrotype
plates are found to be almost int estruc
tible. They not only can be printed
from an almost unlimited number Of
times, but they are better calculated
than those ofcopper to withstand those
inevitable accidents constantly occur.
ing in printing establishments. Prinr.
tiers are sometimes obliged to set aside
as useless their best plates, which arc
often damaged by grain of sand or
by chance knot in the paper. These
accidents not only involve the expense
of renewing the plates, but sometimes
occasion Interruptions and delays in
works of very pressing nature. These
are some among the many advantages
which may be expected to accrue from
the introduction of iron electrotypes. "
Improved Form Of Boiler.
A new sectional boiler, noticed in the
English papers, is believed to possess some
important advantages oyer similar con-
structions. 1t is made with the tubes bent
into the shape of a worm, or partially so,
the pitch or amount of bend varying with
the diameter Of circles of holes in the tube
sheet and the hoigh: Of the boiler, except.
ing only in the centre tube, which, being
from four to ten inches in diameter, &C.
cording to power Of boiler, is etl aight,
with Hanged ends, riveted in the usual
manner to the top and bottom tube sheets.
This centre tube is supplied with a drop
ping plug or damper, futed round the
sides. The use of the plug. damper is this
When the fire is lighted, the water being
cold in the boiler, 1t is raised fully to
establish draught, and prevent the con
densatiOn of the products of imperfect
combustion, in the shape of SCOT in the
smaller tubes; when the fire is we'll under
way, the plug is allowed to drop on its
seat on the top of the centre tube, the
flutes OF notches around its side allo y ing
q certain amount of drauqht to render the
inside surface Of the tube useful as heating
surface.
The advantages claimed fer these spiral
tubes over the ordinary straight uprigh,
ones, are that they prevent the leaking OF
the tubcs-a constantly recurring trouble
i'll upright boilers their spring. like form
permitting easy expansion and contraction,
without affecting their tightness in the
tube sheets; they permit, too, the use 81
the convex lower tube sheet, or furnace
crowns, thus tending to prevent the plate
from cracking through deposition Of slit
etc, they also Increase largely the heating
surface by having much larger tube in
the same height Of boiler. The heating
surface is likewise ola more effective de.
scription, being made to approach, as
much as possible, the best of all beating
surface, the horizontal tube, excepting in
the steam way, or part Of tube above the
water line, which is straight and con-
sequently upright, or nearly 50.