Iowa state bystander. [volume] (Des Moines, Iowa) 1894-1916, 1914-12-18
THE x.RAY.

scientists Of the time. But we can
now see that 1t was the perfectly logi-
cal sequence Of long series of dis
coVerles, following numberless expert.
ments by many individuals with a
scientific toy known as the Geissler
tube. Geissler had demonstrated the
peculiar behavior of electric dis.
charges through different gases con.
nned In sealed tube and under vari.
GUS degrees of vacuum, whereby the
spark became a more or less steady
stream.
Following Geissler, Sir William
Crookes became the chief investigator
along these lines. and by means Of
miniature windwheels and turbines in
his improved tubes, now known as
Crookes tubes, demonstrated that the
current of electricity flowing from the
negative pole and known as the cath
ode stream could be transformed into
kinetic energy. Radiant matter" was
the term used by Crookes to describe
the highly raretied gas, or ultra case.
GUS matter" which he found to pro.
duce certain peculiar mechanical and
luminous effects when charge of high
potential electricity was passed
through it.
AS with all new thoughts, the idea
was fiercely attacked by many of the
scientific men of the time, who strenu'
ously argued against it and endeavored
to prove that both the theory and the
demonstrations amounted to nothing.
But a few choice spirits pressed on.
Lenard demonstrated that the cath
ode stream could be detected outside
the tube as we'll as within it and that
it could be DETECTED or attracted by
a magnet. A professor Of physics IN
the University of Wurzburg, in Ba'
varia, w. X. Roentgen, noted in 1895
that substances such as potassium
platinocyanide became luminous when
brought near to tube exhausted to
vacuum so that the glass was brightly
phosphorescent. About this time also
he noticed that large number OF pho
tographic plates placed within range
of a Crookes tube with which he was
experimenting were logged, although
they were simply protected from light
by the usual light-tight plate holders,
and he began to suspect connection
between the two phenomena. A lew
more experiments and the idea crystal
lized-he viewed his own bones
through the flesh Of his hand and
knowledge of the new ray was born
November 8, 1895.
Because the ray which produced
fluorescence showed him the bones in
the living human body, affected photo
graphic plates while inclosed in light
tight boxes and could not be reflect
ed. refracted nor detected by mag
net Roentgen knew that he had dis.
covered a new and unbroken ray and
he therefore called 1t he'X.ray.
It may be asked how it is possible
to distinguish between such radiatlons
of different wave lengths. This is
achieved through demonstrating by
means of photography, or fluorescent
screen. or the electroscope, the "pene-
trating power" or hardness" of the
short wave emanations after travers'
ing various thicknesses of medium
which absorbs X-rays, such as, for ex-
ample, aluminium. The shorter the
wave length the harder the ray
and the harder" the ray the greater
its penetrating power. Soddy has dem
onstrated the penetration of one-half
inch STEEL This discovery OF the COM
MEX character of the X-ray tube ema'
nations and those from radiant SUD-
stances in general created the need
If system for designating the diner
ont ravs. and they have therefore been
named alpha, beta, gamma from the
Creek alphabet corresponding with
our a, and c.
The original X-ray tube shot the
RAYS from the cathode directly against
tho glass at the opposite end; suDse-
nuentlv a. metal target known as the
anti.cathode was introduced to re-
ooivo the rays, but the bombardment
srou the stream of corpuscles or cleo
trons was so intense that the large:
was soon raised to white heat' anu
Il would become necessary to stop the
~ ..,eu For these and other reasons
which we will discover later radium
WITH w,I its gamma rays seemed to offer
certain cert advantages over the r x.ray
tube. but recently Dessauer of Frank TX.
fort.on- Main has perfected TUBE oy
which he can produce rays practically
identical with the gamma ray from
radium or mesothorium, the ratio OF
hardness being as i to IL. iheee
resnlts were obtained by employing a
snocial and highly efficient water cool
;ne device in the anti'cathode'