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THE MUSIC TRADE REVIEW.
New riethods of
Casting Iron.
American Architect and Builder copies
from La Revue Industrielle a description of
a new method of casting iron. It is well known,
the editor adds, that iron castings are very
liable to "blowholes," "cinders" and so on,
which occur in the middle of the mass and
destroy its strength, or at least its appearance.
These defects are caused by particles of scoriae,
oxide or other impurities, which flow out of the
melting furnace into the ladle, or are formed by
the contact of the hot metal with the air or with
the sand of the mould ; in fact, if the molten
iron is watched as it is drawn from the furnace,
the surface is soon seen to cover itself with dull
lumps of scoriae and impurity, which rise to the
surface. It is usual to fill the moulds more
than full so that the lighter substances may
float to the top and collect in the portion to be
subsequently cut off; but this does not entirely
remove them. M. Van Riet, to give the impuri-
ties time to separate from the melted iron before
it runs into the mould, sets on top of the flask a
sort of little bath tub, lined with some refractory
substance, and presenting three cylindrical hol-
lows of different sizes, communicating with each
other by tangential channels. The iron is
poured from the ladle into the larger hollow,
where it whirls around for a time and then
escapes into the second basin, where it revolves
in the opposite direction. From this it reaches
the third compartment, which is a hole in ihe
bottom, and, as this hole is set over the pouring
hole in the flask, the iron then runs out into the
mould. When the metal is poured into the
large end of the tub, it is seen to whirl around
until the surface is covered with the larger
pai tides of impurity, which collect near the
middle, the centrifugal force developed'by the
whirling serving to separate the purer and more
liquid iron from the light and spongy scoriae,
very much as cream is separated from milk by a
centrifugal churn, or molasses from sugar in the
centrifugal tanks of a refinery. By the tangential
channel the purer iron passes into the second
division, where the same process is repeated, the
scoriae, which are now in fine particles, collect-
ing in the middle, while the liquid metal keeps
to the outside. The third canal, also tangential,
leads this twice purified iron to the third com-
partment, from which it runs into the mould, a
few particles of dross floating up from the mould
and collecting at the top. On cooling, the first
division of the "bath tub," or " poche interme-
diare," as its inventor calls it, is found to con-
tain the large lumps of cinder, while the second
compartment contains a spongy mass of impur-
ity, in the shape of an inverted cone, the base of
which occupies the whole area of the compart-
ment, the pure metal having escaped around the
sides below. In the third compartment nothing
appears but a little ring of particles, the last
to rise to the surface out of the mould. The
castings made from iron thus purified are
extremely sound and solid, and there is no loss
of metal, all the pure and liquid iron escaping
into the mould. The "bath t u b " is easily
cleared out, and is relined for a second operation
by plastering with fire clay mortar.—Scientific
American.
THE Banjo and Guitar Journal for December,
1894, and Jauuary. 1895, published by S. S.
Stewart, 221-223 Church street, Philadelphia,
contains much of inttret>t to banjoists, both in a
literary and musical way.
Sustained Tones in the Piano.
MJft MEANS of obtaining more sustained sounds
®-=s from the piano is thus described in the
Musical News, London : The device consists of
a set of metal disks, suspended from the sound-
board of the piano, and vibrating in sympathy
with the sounds produced from the strings by
the hammers in the customary way. So far as
it has been tried the plan does seem to increase
the volume and sustained power of the tone.
When our mechanicians can fully succeed in
getting a piano to sustain the tones evoked, and
yet to possess all the grades of dynamic force (it
would to a great extent then resemble a fine
harmonium with the expression stop employed),
we shall get a perfect instrument. But will it
be a pianoforte proper ? One great charm of the
piano is the purity of its tones and their evanes-
cent character; these features will disappear if
the timbre is altered by being made completely
sostenuto, and the effect of the blow of the
fingers is not allowed to fade away into com-
parative silence.
THE Indicator says that Col. Dan. F. Treacy,
of the Davenport & Treacy Company, illumi-
nated the dark corners of the trade in Chicago
for three or four days last week. He has made
a trip to several of the leading points in New
York and Canada and finds that business is
moving along in a satisfactory manner.
THE Hallet & Davis Company, Boston, have
sold all of the very handsome line of instru-
ments which they had on exhibition at the
World's Fair, with one exception, a white satin-
wood, inlaid with pearl.
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