The Portland daily press. [volume] (Portland, Me.) 1862-1921, 1896-02-08
PROF. ROENTGEN'S DISCOVERY.
Review of the Experiments by Prof
Silyanus p. Thompson.

What He Says of tile Wonders full Addition
tiles to be Unfolded,
II those who take lively interest II
the discovery of Prof Roentgen Prof
Sllvanus 2. Thompson is prominent A
contribution by him on the subject t.
The Saturday Review has been published
The Electrical Engineer, as follows:
g very singular scientific discovery
has just been made by Prof. Roentgen
of Wurzburg. Itdepends on the trans
parency Of materials to those kinds of
radiation which are invisible to our eyes.
For long it has been known, and it was
a favorite point in the lectures of tn late
Prof. Tyndall, that the invisible waves
of heat which are stopped by metals can
penetrate through rock salt and that the
equally invisible actinic Cor photograph
ic) waves can penetrate through quartz
but are largely stopped by glass. Then
Abney discovered means of photograph
ing the heat waves, and succeeded in
photographing. by it's own invisible
lie
of boiling water. Later it was fou nd
that in opaque screen of the hard, black
india rubber, known as ebonite, is trans
parent to heat waves.
! Some seven years ago, by the research
es OF Hertz and of Lodge, it became
known that electric waves, though ar
rested by metallic screens, can pass readi.
~ through the human body. Meantime,
discovery had advanced in another direc-
iton. In Crookes's classical researches on
electric discharges in high vaoua. he dis
covered that in the extremely attenuated
gaseous residues In the tubes which he
employed, the discharges from the mega
tive pole, or kathods, can cast shadows on
the walls of the enclosing tube. These
kathodio rays have been investigated by
many experimenters, including Gold
stein, Wiedemann, and Lanard, They
were found to be ouriously active in ex
citing phosphorescenoe, and to travel
quite differently from ordinary rays of
light The lamentered Prof Hertz added
to these discoveries the observation that
these kathode rays, though incapable Of
passing through glass, would pass
through thin sheets of metal. which
woud be quite Opaque to ordinary light.
And now Roentgen has put crown
ing touch to these facts by the remark
able discovery which has excited the
! Viennese press. He has succeeded in
finding means of photographing an OBJ
ject of metal though it may be all the
while shut up in wooden case A
special source of light Ga Crooke's tube
stimulated by electric discharges) is
placed behind and the camera, or rather
the sensitive sheet, in front Of the wood
en- box. These special radiations pass
through the box more readily than if it
were of glass, but cast Photographic
shadow of whatever metal object may
be in the interior. This is scarcely phot-
ography, in the ordinary sense of the
word. 1t is rather the Photographic regis
tration of the shadows.
"Glass lenses cannot be used to concen-
trate these rays, hence they cannot be en-
ployed to form images. If sheet of sem
sitive paper is in turn. shut up in wood
en- box, and an object of metal is placed
in front, its shadow as cast by the radia-
tions from the Crookes tube is imprinted
on the paper. No exposure (as the
photographer understands it, is neces-
sary. Indeed, the sheet of paper may be
| shut up in one box and the metal oiaot in
another, and yet the photograph may be
taken. In the same way Prof. Roentgen
is able to photograph mans skeleton
through the skin, flesh and clothes.
which for this purpose are Photographic
cally transparent, while the bones ara
opaque like the metals. Placing his own
outspread hand outside the closed box
containing the sensitlzed sheet he oh
tanned print Of the finger bones and the
rings on the fingers.
Whatever, then, the new kind of
light may be that produces these effects.
it differs both from ordinary light and
from the ordinary Photographic rays, as
well as from the visible kathodic rays
discovered by Crookes; for the latter pass
through metal, but are stopped by nom
metallic subtanoess. Prof. Boltzmann.
whose authority in physical optics stands
undisputed, regards the discovery as of
the utmost Importance from the scientific
standpoint for it reveals the existence of
phenomena not explained in any of the
accepted theories of light or,of electricity.
For the multitude the discovery is
no less wonderful; it adds one more to
the marvels Of science. To photograph
IN total darkness seems inexpicable;
out that We should be able to photograph
through walls of wood or through solid
and opaque bodies is little short of a
miracle. We shall now be able to realize
Dickens's fancy when he made Scrooge
perceive through Marley's body the two
brass buttons on the back Of his coat. We
shall now be able to discover photograph |
!cally. The position of a bullet in mans
body. Even stone walls will not a prison |
make TO the revelations of the camera"