Green-Mountain freeman. [volume] (Montpelier, Vt.) 1844-1884, 1881-05-11

The scientific papers. among them the
London Engineer, the ADlericGn Mdnufdc-
Lurer,S and the illustrated Scientific NetUs,
have been aroused to an unusual spasm of
speculative energy by certain little in
strument, styled the fusng disk, in use in
large iron and steel establishments in
Pttsburg, Pennsylvania, whose operation
raises new and diffiult question in molec
ular physics that it will require accurate
experiments TO solve. The fusing disk is
described as IN instrument for cutting cold
steel by current of air, and although at
first glance resembling the cold saw has
nothing in common with it in its mode of
operation. 1t is, of course, a familiar fact
among engineers that a disk of soft iron
revolving at high velocity will sever II bar
of the hardest steel in few seconds, pro-
vided that the contact and pressure are
properly regulated. The fusing disk, al
though it might he mistaken for the cold
saw in external appearance, operates upon
an altogether different principle, and one
whose efficiency is not readily explained
from hitherto ascertained laws respecting
the fusion of metals. There is no actual
contact between the edge of the disk and
the bar 10 be severed and the work is done
entirely by local fusion of the latter with
out material elevation of the temperature
of the disk, which consists of thin cir
Gle of soft steel almost 81 feet in diameter,
making 230 revolutions minute-equiva-
lent to (3tx3. l41592x230) an angular ve-
locity of 1928 9Sl56 feet The bar to be
cut must be round, and firmly secured in
front of the disk, revoved at the rate of
about 200 revolutions per minute in the
same direction. Thus arranged, without
actual contact, bar of steel Ii inches in
diameter may be severed in from 2 to 10
seconds by fusion. The groove fused in
the bar as the disk advances is usually
about once and a half the actual thickness
of the disk. and its bottom is always in
advance of the margin about the same
distance. If the bar is not in revolution
| the disk cuts its way through after the
manner of the cold saw, and the debris
which drops from the incision is a finely
divided iron oxide while, on the other
hand, when the bar is in motion the drop
pings consist of small globules of metallic
iron, thus showing that molecular tension
is the only agent concerned in the work.
rhe puzzling question, if heat is to be re.
garded rs the agent OF fusion, is to explain
generation of heat sufficient to fuse a
bar of steel in to 10 seconds by the sim
Pile revolution in the same direction, at no
extraordinry velocity of the fusing disk
and the contiguous bar. The disk never
becomes sensibly heated in the operation,
and while the ends of the bar are percepti-
big raised in temperature the molten metal
that drops from the cut, though sensibly
fluid in its texture, can be caught in the
palm of the naked hand of the operator
without detecting any rise that is in the
least inconvenient. 1t will be obvious,
therefore, that there is question of molec-
ular physics raised by this simple inven-
tion which cannot be solved by reference
to hitherto ascertaned laws of physics
Engineers and physicists in the journals
named have exhausted all the received
doctrines of occluded heat, molecular ten
sion, ETC., in trying to account for this
remarkable phenomenon, but it has not
apparently occurred to any of the parties
to the discussion that the probable cause
of the fusion is to be sought in the gene
ration of powerful electrical current by
the revolution of the disk and bar in the
same direction, and the foundation of Il
voltac are at the point of fusion produ c.
ing intense local molecular tension. .-NeW
York Times.