The news & observer. [volume] (Raleigh, N.C.) 1894-current, 1896-03-10

1T seems now questionable whether
/ the impression on the plate is a direct
i effect of the X rays, or a secondary
result induced by the fiuorescenee of
the metal of the plate. Films can re-
ceive the impression as well as ordi-
nary plates.
| ] have not been able to show ex-
/ perimentally that the X rays cause
heat. 1t is certain that all the X rays
falling on a body do not leave it as
such. The retina Of the eye is quite
unsensitive to these rays When placed
close to the apparatus the eye sees
nothing.
x RAYS NOT TURNED ASIDE.
After my EXP ments on the trans
parency Of increasing thickness of diff
ferent substances, / proceeded to in
vestigate whether the X rays could be
turned aside, as the rays Of ordinary
sunlight can, by a prism Investiga-
| tions mace with prisms made Of vari-
! GUS materials showed no deviation of
I the rays, either on the Photographic
or the fluorescent plate. For compar-
4 ison sunlight rays were allowed to fall
on the prism as the apparatus was set
/ up for experiment They were devil
ated from ten millimetres to twenty
millimetres.
On account Of the Importance of this
question it is desirable to try in other
ways whether the X rays are suscepti-
| bic torefraction Finely powdered bodies
allow, in thick layers, but little of the
| incident light to pass through, in con-
sequence Of refraction and reflection
In the case of the X rays. however,
such layers of powder are, for equal
masses of substance, equally transpa-
rent with the coherent solid itself
| Hence we cannot conclude any regular
reflection or refraction of the X rays.
/ The research was conducted by the aid
1 Of finely-powdered rock salt, fine cleo
! trolytic silver powder, and zinc dust,
already many times employed in chem
! zeal work In all these cases the re-
suit, whether by the fuorescent screen
or the Photographic method, indi-
Gated no difference in transparency be-
tween the powder and the coherent
solid
1t is here obvious that lenses cannot
be looked upon as capable of concen-
trating the X rays; a glass tense of
large size does not have any action in
bringing the rays to a focus.
RESULT OF AN EXPOSURE.
/ exposed a plate, protected by a
black paper sheath, to the X rays, so
that the glass side lay next to the vac
uum tube. The. sensitive film was
partly covered with star-shaped pieces
Of platinum, lead, zinc and aluminium.
On the developed negative the star
shaped impression showed dark under
platinum, lead and, more markedly,
under zinc The aluminium gave no
image. 1t seems, therefore, that these
three metals can reflect the X rays;
as, however, another explanation is
possible, i repeated the experiment
with the only difference that strip
OF aluminium foil was placed between
the Photographic film and the metal
stars In the result the images APP
/ peared AS before, thus pointing to the
existence of reflection (of X rays
az metal surfaces.
1t is known that Lenard, in his inyes-
legations on cathode rays, has shown
that they can pass through all bodies.
Concerning the rays, the same may
be said. But air absorbs the X rays
much less than the cathode rays. 9th
or bodies behave like air, they are more
transparent for the x rays than for
the cathode rays.
Al further distinction between the
cathode rays and the x rays result
from the action Of a magnet. | have
not succeeded in observing any devia-
ton of the X rays even in very strong
magnetic field.
As the result Of many researches, it
appears that the X rays have their
source at the place where the most bril-
liant "phosphorescence, or violet
light is seen about the vacuum tube
during the continuance of the electric
discharge. From this point the X rays
spread ia all directions. The X rays
proceed from the outside of the tube,
whareas the cathode rays proceed from
the interior
The X rays can be generated in other
kinds of tubes than those made of
glass. ] have obtained them in an APP
paratus closed by an aluminium plate
two miIlimetres thick. / propose later