New-York tribune., 1896-03-29
THE NEW FIELD OPENED BY EDISON.
HOW TIE INVENTOR SOLVED THE vAcUUa
ppopl.EM-PRODUCrION AND POWERS
OF TILE FIIOROSCOPT.

HOW TIE INVENTOR SOLVED TIE VACUUM
PRoDI.EM-PRoDUCrIoN AND POWERS
OF THE FLrORoscoPT.
Thomas A. Edison has apparently brought his
processes the development OF tho results OF tho
rays TO a point OF practical perfection. BY his
discovery OF the uorescent properties OF tho tung-
state OF cn.c!um and its remarkable senstiveness
20 the rays. he has practically opened new
n-d to the experimenter The old process OF photo
graphing is entirely dispensed with. ana the ex-
perlmenter nov with the naked eye. instsh-
tnneously the objects sought 10 be investigated
Mr. Edlson's great trouble for long time was IN
the difficulty OF preserving satisfactory vacuum In
the C'rookes tubes while under the current Tuoes
which gave excellent results at first. In very few
minutes use weakened and showed tie V'oiet
cathode rays thus indicating n low vacuum mat
was practically useless for the production OF the
rays
Mr. Edison told n Tribune reporter that this
particular phase Of problem worried him and
caused him moro hard thinking and study than all
the other points that under his study AT last
A bright iloa came to him. AS he said i beheVe
that that bcggar R6ntgen didn't tell all that he
knew" Accordingly, after n good deal OF study.
Mr. Ellison struck tho idea that the vacuum
should not be produced and the tube seaed up ana
then left to It's fate but that the proper pro-
cedure was to have the vacuum apparatus working
constantly so as to keep the vacuum. when once
produced constant. This proved TO be tho solution
OF the problem.
A description OF the vacuum apparatus. whlch IS
that in constant In all the electric lamp works
may prove interesting 1t consists. In non-techni-
cal terms OF upright tube of glass about three
feet IN length and OF small diameter To the top
OF this IL attached the tube lamp in which It Is
desired 70 produce the vacuum. the connection be-
ing made by rubber ring Into the side OF this
upright tube. the top Is inserted branch tube
connected at the top with a reservoir OF mercury.
This IS the entire apparatus in It's essential parts.
t,,ba Ia ttAn IU Tor thA
air 10 be exhausted. stop cock is opened In the
side tube, and a stream OF mercury runs down and
into the main tube. The Interior diameter OF this
main tube Is nicely regulated. TO be a tr!ne
smaller than the normal diameter OF n globule OF
mercury. As the mercury drops into the main tube
each globule In lis descent pushes down the tube
In front Of 1t little air. exhausted from the upper
part OF the tube. AS the vacuum Is formed, the
mercury In the lower part OF the main tube stands
In supported column. and the height of this column
indicates the degree OF vacuum that has been pro-
| duced.
practical Is that OF small box closed on all s!des
inside the box Is powerful electric battery for
producing the primary current and induction coil for
the inducing OF the secondary current and ono or
more Crookes tubes These latter are connected with
| the vacuum pump Just described which for con-
venience Is paced on a plank at the rear Of the
box. Tho top OF the box of thin plank Of
fers practically resistance to the passage Of tho
| X rays. so much for the productive part. The
remainder Is the optical part OF the apparatus
and this is the Simplest possible. Readers OF The
Tribune will remember the old stcreoscopic instru-
mcnts which fitted closely to the ego and contained
two lenses arranged that their focus was iden-
teal Now. imagine tho outer OF this stereo-
| scope to be extended for six or eight inches and
| there ending In an oblong parallelogram. perhaps
bx9 In size. Take out the lenses entirely and
| tho large open end with piece Of cardboard or
| cloth on which the minute crystals OF tunRstate
| OF calcium have been strewn and held In position
| by finn OF co.lodion. Then one has the Edison
'Fluoroscope. and this Is all that there Is to It,
In use this IL simply applied to the eyes that the
outer light Is excluded and when placed anywhere
| In the field that Is permeated by the rays, tho
film OF tungstate OF calcium crystals at once g;ows
with wonderful nuorcscence.
Tho application Is evident. Place the hand or
the the leg OF man any other object
that II IL desired to examine top OF the box and
let the current be turned With the huoroscope
| the Investigator sees pictured before him with
startling disnctness the bones Of the hand or arm
the may be- The flesh ceems entirely to
disappear under the X rays and only the bones
that imperviouus to them EAST their shadows
on the film.
Mr. Edison believes that the day will soon come
when In every hospital there will be these
arrangements TO enable surgeon to examine
minutey and accurately fractures and all other IN
Juries as to act nelligently In their reduction
setting.