Richmond dispatch. [volume] (Richmond, Va.) 1884-1903, 1896-02-21


Cathode rays and the Rosntgen pho
tographs were discussed at an espe-
cially interesting meeting Of the Frank
lin Institute last evening. A paper pre-
pared by Professors Edwin j. Houston
and a. Il. Kennedy. and read by Pro-
fessor Houston, gave q careful review
of the recent discovery and investiga-
lions along this line. A discussion fol-
lowed. participated in by the scientific
men of the city. Apparatus from the
laboratory Of the professors was exhibit
ed, and the process used i'm making the
photographs with the aid Of the cathode
rays explained.
In their papers Messrs. Houston and
Kennedy said: Professor Roentgen de-
scrbes in his paper the method he
adopted for obtaining the peculiar form
OF radiant energy now generally known
as the Roentgen rays. and for which
he proposed the provisional name OF "
rays. on passing the discharge from n
large Ruhmkorff coil through a suitably
exhausted tube OF the Hittorf. Lenard
or Crookes type. peculiar effect in
visible to the eye is produced in the
region outside the tubei
These rays, produced outside the
vacuum tube by the cathode rays with
In the vacuum tube, may be called the
AdJs
THE LENARD RAYS.
'In common with the cathode rays
the Lenard rays possess the power OF
producing fiuorescence I'm fluorescent sub
stances upon which they impinge. They
differ from the cathode rays In the
fact that In the air they are visible TO
the eye as a family glowing stream or
pencil, which rapidly diminishes In In
tenslty at comparatively short distances
from the window
1.-THE Roentgen rays are invisible to
the naked eye. Roentgen states, as a
result OF observation. that his rays are
apparently incapable OF reflection. re-
fraction, or interference. III refraction
does exist. IL must be OF very limited
amount. These facts have led Roent-
gen to suggest that his rays are not
light in the ordinary physical sense OF
the term-that Is. that they do not con-
sist OF q transverse vibration propagated
in the ether according to electromagnetic
laws-but that possibly, they may be
a longitudinal motion propagated in the
ether. condition which Professor S. p.
Thompson has happily named ultra
violet sound and which other have
called ethereal sound and longitudinal
light
CAN MELT THE TUBES.
"The Crookes tubes, as ordinarily con-
structed, are not designed to stand the
molecular bombardment OF the cathode
rays, when Of fairly great power. for any
considerable length OF time. Indeed. at
times the heat produced by the molecu-
lar Commandment OF the cathode rays
is sufficient to melt .re glass walls Of
the tubes
Since the hgh-frequency discharges
obtained by the use Of a Tesla coil are
not characterized by such marked heat
Ing effects, either at the walls OF the
tubes or i'm the electrodes, they are
greatly to be preferred for. producing
shadowgraphs. Independently of this.
however. they appear to produce a more
powerful image"
Speaking OF the electrical effects of the
rays they said: Professor J. j. Thomson
has recently made the extremely import
ant discovery that the Roentgen rays
tend to discharge an electrified body on
which they imringe, and this. whether
the charge OF the body be positive or
negative. Professor Thomson finds that a
charged body constitutes a more sensi-
tive test for the presence OF the Roent-
gen rays than Is afforded by either
sensitive Photographic plate, or
fiuorescent screen. This effect takes
place whether the charged body be COW
cred by layer OF parafine, sulphur. OF
vulcanite In other words, as Professor
Thomson points out, the remarkable
fact exists that an insulating layer be-
comes electrically leaky while being
trayersed by the Roentgen rays"
Upon the composition of the rays they
say: Or Lodge has shown that when
polarized ultraviolet light strikes such
negatively charged polished plate, II
IL most effective In producing discharge
when striking at an angle, instead of
perpendicularly. and consequently. the
discharge may, perhaps, be effected by
a longitudinal component of the impact.
This seems to favor the supposition that
the Roentgen rays are longitudinal ethe-
real vibrations.
Summing up, then, while 1t Is far too
early to form a reliable conclusion con-
corning the nature Of the Roentgen rays.
such evidence as does exist would appear
to favor the theory Of longitudinal vibra-
tons in the ether.
Whatever may be the future Of the
Roentgen rays. so far as their practi-
cable applicability or scientific value Is
concerned. great praise must be ACCORD
ed TO Professor Roentgen for the ex-
ceedingiy interesting and important con-
tributon ne has made 10 this branch OF