The San Francisco call., 1896-02-18

by metal of a piece of metal the lack s OF
homogeneity of which was brought out by the
rays, etc.
To show the rectilinear propagation OF the
Y rays there is q pin-hole photograph, Whlch
apparatus covered with black paper. The
image is weak, but unmistakably correct.
| looked very carefully for interference pne-
nomena with Y rays, but unfortunately, per.
haps only on account of the small intensity OF
the rays without success.
Researches TO determine whether electro
static forces affect X rays in any way have
been begun, but are not completed.
WHAT x-RAYs ARE.
If we ask what rays which certainly can
not be cathode rays really are, we are leg at
and chemical properties, 10 thlnK OF ultra
violet light. But we Immediately encounter
serious objections. If X rays be in reallty
ultraviolet light this light must possess the
following characteristics
(a) 1t must show no perceptible refraetion
on passing from air into water, blsulphlde OF
carbon, aluminium rock salt, zine, etc.
(b) 1t must not be regularly reflected to any
appreciable extent from the above bodies.
(c)- 1t must not be polarizable by the usual
(d) Its absorption must not be Influenced by
any of the properties of substances TO the same
extent as ii is by their density.
In other words, we must assume that these
ultraviolet rays behave in quite different
manner to any infra-red, visible or ultra-V1olet
rays hitherto known. could not bring myself
to this conclusion, and have, therefore sought
another explanation.
There seems at least some connection be-
tween the new rays aud light rays in the
shadow pictures, and in the huoresclng and
chemical activity of both kinds OF rays. Now,
it has been long known that besides the trans
verse light vibrations, longitudinal vibrations
might take place in the ether, and, according
to the view of different physicists, must take
place. Certainly their existence has not up
till now been made evident, and their proper
ties have not on that account been expert
mentally investigated.
May not the new rays be due to longitudinal
vibrations in the ether?
l must admit that have put more and more
faith in this idea in the course OF my research,
and 1t behooveS me, therefore, to announce my
suspicion, although l know well that this eX-
planation requires further corroboration
WURZBURG PHYSICAL 1NsTITUT DER UNIVERSE
TAT, December, 1895.
In commenting editorially on this COM
munication. the London Electrician has
this to say:
1t may not be without interest at the present
moment to recall the main points of difference
and OF similarity between Roentgen and
Lenard rays-to use two brief and convenient
expressions. Roentgen rays are not DETECTED
by magnet; Lenard rays are Roentgen rays
suffer lar less absorption and diffusion than
Lenard rays Lenard found that his cathode
rays failed to pass through anything but the
th1nnest soap films, glass and aluminium folI,
ETC.; the Roentgen variety will traverse sew
eral centimeters OF wood and several miili-
meters OF metal or glass. Roentgen was able
to take "shadowgraphs" and detect fuores-
cence 200 centimeters away from the
discharge tube; six eight centimeteTS
were enough to wipe out Lenard rays in air
at atmospheric pressure, and even in hydro
gen gas, at only 0.0I64 millilneters pressure,
the radiation length for cathode rays was
only 130 centimeters. hydrogen at atmos-
pheric pressure behaving as decidedly tur-
pid medium. These are, however, rather diff
ferences in degree than in kind Lenard rays
emanate, of course, from the cathode itself
but Roentgen rays. according to their dis
coverer, start from the lumiGiscent spot on
the glass wall of the discharge tube at which
the cathode rays terminate. The points of
similarity between Roentgen and Lenard rays
are their Photographic activity, their recti-
linear propagation las evidenced by the sharp
shadows CASH and the fact that in both cases
it would seem the total mass of molecules
contained in unit volume OF any substance
practically determines its transparency All
things tend to show that we are on the verge
of great scientific discovery, which may
ideaS.n