The morning times., 1896-02-19
Calls ITl scOTOsCOPE
Prof. Harding's Device 10 Get Pic
lures From Roentgen Rays.
NO SILHOUETTE SHADOWS
interesting Talk With the Inventor
IN This City-Patent to BE Applied
for-Living Pictures Derivable
FROM Gold Leaf and yuIcanite-
An inexpensive Process.

| - 1AhOA l1uI whose lDIerVle W,
published recently In The Times, on the
subject OF taking photographs from the
| eye or pictures thereon fixed by external
| opJects and 10y thought, attracted much
| atVeiltion, Is again in the city and is at
Tue st. James Hotel, where he returned
| yesterday from Baltimore, where he had
! gone TO perfect some experiments relating
TO the Roentgen rays.
ffor. harding also spoke in The Times of
the practlcai proofby himself OF the produc-
uoh of sound by reflex action from the
| Drain or By will power without physical
eiiort.. ana the making OF the thought
auuioie 10 another person with whom the
1hilker was in connection, by the ordinary
| phonograph tubes.
Prof. Harding said yesterday that he had
now determined to apply for patent for
another development of one of his ideas,
winch had become possible of practical
| development since the agitation of the
| Roentgen rays.
| His invention is called a scotoscope. which
by an ingenious application OF the rays
enables hin 10 get pictures, not of the
| shadowgraphs cast by the cathode rays,
but of the objects themselves. The expert
inents on this line are not very expensive. in
astnuch as electrical apparatus is not
necessary. Speaking of the new idea yes
terday, Prof. Harding said:
WITHOUT ELECTRICITY.
ut will be of interest to experinlenters
| with &-rays toknow that it is not Unnecessary
| 10 have any electric discharge in a vacuum
| tube, for tie same rays are found in the
spectrum OF magnesium and to a greater
| extent in calcium,
Calcium carbide burned in the oxy-
| hydrogen flame of the ordinary lime light
| produces wonderfully sharp and distinct
shadowgraphs., y special flash light car
fridge of suitable oXidizing agent and a
| cyanide OF some of the aIkaH or earthly
metals, such as cyanide of calcium, Will, in
| my opinion, be, the most conven lent and
| efficient source OF the necessary actinic
energy for producing sootographs where
! ever they may be considered useful or or
| namental. TbissmeaRs is OF great import
| ance in producing visual or optical effect
| of the SHADOWS instead of chemical rho-
| tograph." crs s.-s
| How this may be done Prof. Harding cx-
| planned as fo4ows:i The instrument he calls
| lshadowscope, or TO give it the Greek
term the scqtoscope.
SCATTERING THE RAYS.
The radiant energy from Crookes tube
is of course invisible. but as it strikes the
glass there is a splitting up, or miniature
bonbardment, as Mfr. Tesla used to cal
it, and some OF tie slow rays get double
| quick and vibrate fast enough to become
visible Just at the surface of the glass.
This is knowTli as fluorescence. These
rays 20 through the air unseen, but Just
at the surface of fcertain objects, as glass
or metals they turn fIuorescent in part
again and produce some visible light. This
fluorescence is especially increased by
diminution of pressure of the gases, and
| years ago l used to toy with an ordinary
incandescent lamp in the fields of the
| lines OF force or X rays and see them shine
with weird phosphorescent fluoresceut
glare.
NOW let us 20 one step further aud make
the scotoScope. A sheet OF gold leaf shell
laced to a thin plate of vulcauitc is made
to form one side of a box, plate of glass
the other side. The gold surface is to be in
side and the air must be pumped out to
form a vacuum. In this We have fluor
oscope complete. If this is held behind
the object penetrated by the Rocntgen
rays. most all the energy that strikes the
gold leaf is turned to light aud We can
plainly see all the shadows cast by bones
bullets, needles. etc. The hand, for in
stance, held near the fiuorescent plate can
be moved ard turned so as to apply the
Iluminant to any part
SEE THEM DIRECT.
'It is evident that il the new light can
photograph hidden objects the Horoscope
will enable us to see them direct; and evenif
we can only photograph shadows as pres
ent it is of more Importance to see them
direct
~ hold that the light in the scotoscope
can be reflected and refracted and focused
by a lens; that this light so produced is
strongly actinic and is the only means by
which TO reduce pictures to g. small size
and having them fixed by direct vision they
can be studied under the microscope. The
vital difference and the value OF the dis
covery is that we obtain by this means not
shadows of shadows but pictures direct
from the objects"
Prof. Harding thinks that all that is
practically known of the Roentgen rays as
producing practical results can be stated in
few paragraphs he has recently wit
messed some OF the experiments of the
famous Tesla
o