Eagle River Democrat. [volume] (Eagle River, Vilas County, Wis.) 1893-1896, 1896-02-24
The New Photography at the Univers-
ity.

process, recently discovered III
Germany of photographic
through Opaque matter, has been
carried on by DR., L. ". Austin
in the physical labortory of the
University of Wisconsin during
the past week. Photographs of
the human hand have been taken
in which the bones show clearly
in the midst of the less distinct
flesh. Another photograph
shows pile of coins in a closed
wooden box, the coins coming
out distinctly and even showing
family the overlapping parts,
while the position of the sides Of
the box appears only as a hazy
outline, though a screw inlbed-
ded in the wood is sharp and
distinct A picture Of a revolver
shows thespring and other parts
as though the wooden handle
had been removed A welded
iron ring was also photograph
ed, and the weld appears plainly
in the picture, although it is
hardly to be discovered in the
ring itself. The process of tax
ing the pictures may be briefly
explained as follows: A closed
glass tube (Crookes' tube) is
used from which all but about a
millionth part of the air has been
withdrawn. and which contains
two metallic electrodes which
are connected with the poles
of an induction coil The
negative electrode or katl1ode, IN
the tube, ism the form If a round
fat disk and when the current
is started rays of energy, known
as kathode rays, start out from
this. These rays show them
selves in the tube by. the bril-
liant phosphorescence at the point
where they strike the glass. 1t
was formerly supposed that they
pass through the glass aud make
their presence known outside by
their action on the photograph
ic plate. The exact nature Of the
rays is not understood, but it is
supposed that they are vibra-
tions in the ether, perhaps some
what like light, though unlike
light, they apparently cannot be
reflected or bent from a straight
path. They pass through all
light substances like wood, pap
err ETC., like light through glass,
but they seem to be stopped or
absorbed by all matter in pro-
portion toits destiny, SO that,
if any dense substance like a
metal is placed in their path it
makes a shadow of greater or
less depth like apartially Opaque
object in the sunshine, and this
shadow is shown on the photo
graphic plate. In taking the
picture no camera is used, as the
rays would not be refracted by
the tense. The Crookes' tube is
placed two or three freet from
the plate holder and pointed to-
wards it. The slide of the hold
er remains closed, as it is trans
parent to the rays and the OBJ
ject to be photographed is plac-
ed close against the slide. The
induction coil which is connected
with the tube is put in operation
for a space of time from a few
minutes to an hour, according
to the density of the object to be
photographed and the strength
of the tube. At the end of this
time if the plate be developed as
usual a distinct shadow picture
of the object will be seen.
The new discovery, which IS
certainly one of the greatest Of
recent years, promises to be of
vast practical value in surgery,
as by it's means fractures of the
bones, bullets, calcareous depos-
it's and the like can be easily To-
Gated. The rays are SO sensitive
to differences of thickness and
density, as was shown in the
case at the weld in the ring be-
fore mentioned, that if Crookes'
tubes of sufficient power can be
made they can perhaps be used
to detect flaws in metal castings
and thus prove Of the greatest
value to the engineer.