The Princeton union., 1896-03-12

These Are Photographs Taken
houncement made by him. Prof. Dol
bear Of Boston announced in April.
1901: 1T is actually possible to take
Il photograph Of an object in absolute
darkness with the ether waves set up
by an electric machine" The fact
established. however, by Prof. Roent-
gen in his discovery is that these ether
waves, now known as a ''cathode ray"
which are invisible to the naked eye,
will pass through Opaque substances.
such as wood ebOnite, many kinds Of
metals. f1eShy tissues and other seem
inGly OPAQUE substances.
Prof. Draper, about fifty years ago,
discovered that Photographic action
takes place in that region of the solar
spectrum which is beyond the violet
raw, and at a later date Abbey desig-
mated that this action was below the
red ray. Thus it has for many years
been known and clearly demonstrated
that the luminous ray which would
affect the eye is not Il necessary es-
s;,nrial in making Il photograph. Pro
fessor Hertz has demonstrated that
the waves in the ether produced by
electrical means could be refracted, re-
hected and polarized, the same as the
ordinary light waves. There is, how
ever, 4 large amount of diversity of
opinion on this matter, and MANY
scientists, who have been and are
carefully studying the cathode rays,
differ widely from the assertion made
by Prof. Roeutgen that the cathode
ary can be refracted reflected and pol
arized.
+ On the whole subject matter there is
yet much to be discovered which will
no doubt be revealed by careful study
and experiment in time.
= Just to explain to those who do not
know this apparatus, and who may
have such a vague idea of what it
generally is and how it works, is fit
ting at this stage.
In the first place, all theory and
thought of something like a photo
graphic apparatus must be dispelled.
The apparatus has neither camera nor
lens. and the results are obtained with
out even exposing the naked plate to
the cathode ray. The CroOkes tube is
an ordinary glass globe, and at either
end are poles for the electric fluid from
an induction coil to pass through. The
ray is Of a greenish-yelloW, and seems
to float around the interior Of the tube
in "A Wavy manner. This is the light
giving the wonderful result, and the
magic ray upon which there is so
much diversity of opinion and the
properties Of which have caused so
much controversy.
This cathode is difficult to describe
in ordinary language. 1t may be de-
scribed as small disc, or plate of alu-
minum, inclosed in glass bulb from,
which the air has been previously ex-
hausted. Opposite the cathode is the
ancde, the terminal of a wire connect
ed with the batteries. When a power
full current is passed between the an
ode and the cothode, and circuit Gre
ated, a light results with rays.
Let the reader further follow in the
result Of experiment, and perhaps he
can then have an idea Of what the ap-
paratus really is and how it works.
An ordinary sensitized silver plate,
the same as used in photography, is
wrapped in three OIL four thicknesses
of orange-colored paper, or, for that
matter, placed in a dark slide, and the
shutter, if Of the proper cardboard,
left closed. The plate is thus protects
ed from the white light or ordinary
Photographic ray. The plate thus
wrapped or slide is placed under the
Crookes tube, and the object from
which the result is required is placed
on top Of the slide or vering. The
Crookes tube is arranged about three
OF four inches from the object, so that
the rays coming from the tube will fall
directly perpendicular on the object.
The electric fluid may be generated in
an ordinary wet or dry cell and then
passed through q Ruhlnkorf coil. The
electric fluid is turned on, and the
length of exposure largely depends on
tn. number of Interruptions Of the
electric current. The exposure for q
Tesult through an inch board would Re