St. Tammany farmer. [volume] (Covington, La.) 1874-current, 1896-07-25
SOURCE OF .x" RAYS
Conclusloas Arrived at BY m Emioen
Engllsh Sclentist.

10Sll00 SC100t0ts
AS to the source of the rays, l, like
others, have made many experiments,
and the results are definite enough.
When the rays from the cathode, inside
the vacuum, impinge first on a glass
surface, then that surface is the source.
1t is not as if the cathode rays penetrat-
ed the glass and proceeded on their
path; it is not AZ if the glass surface
were a wave front, from every point OF
which ray penetrates normally; the
glass radiates X rays just as a red-hot
surface radiates light. From every
point cone of rays starts in all direc-
tions, and there is no mutual intcrfer-
ence in the lateral directions, as there
would be between a number of similar
sources all of the same phase. Every
point of the glass radiates independent
", like hot surface, in fact. The best
experiments of this kind were those in
which I used a magnet to defect the
cathode rays on to any chosen spot or
patch of the glass, and then took
shadow photographs through Sits and
holes placed at measured distances.
The shadows of wires placed at dis
tance from the plates, taken through .
narrow slit at some distance from the
wire, show that if the X radiation con-
sists of waves at all those waves must
be very small There has been nothing,
as yet, to discriminate between longi-
tudinal and transverse oscillations.
Transverse must be considered az the
most probable at present; but then 1t Is
not certain that they are waves at all.
II waves, they must be very small ones,
and the question whether they are
transverse or longitudinal is almost q
minor consideration if it should turn
out that the wave length is comparable
to the size of molecules. The interest
and importance of such an instrument
Of investigation as radiation with that
size of wave whereby indirectly mole
cules themselves would hereafter be
rendered diffractionally visible are inn
mense.
When the cathode rays do not first
strike the glass, but first strike a piece
of metal inclosed in the bulb, then its
behavior depends largely on what it is
connected to. My experiments on that
point are not complete, but this much
is certain, that If the bombarded piece
Of metal is attached to the cathode. SO
that it is unable to receive any electrical
discharges from the cathode stream,
then it either declines to act as source
of rays at all, or else emits radiation
of the most feeble kind, which can with
out difficulty be attributed to second
ary cause. But. on the other hand, if
the bombarded disk be connected with
the anode, SO as to be able to receive the
negative charges of the cathode stream,
then it acts as a most vigorous source.
In low state of vacuum every part OF
the bulb keeps perfectly cool. and the
whole energy supplied seems to pass of
in X rays.
The crop of assertions about the de-
lection of Y rays from all manner of alb
surd sources has somewhat dwindled
of late, and the loss is a bearable one. A
serious attempt must be made to OBJ
serve il the sun emits them by exposing
suitable objects. such as bullets embed
ded in cork. in front of protected plates
on mountain tops, this summer. The
atmosphere, being equivalent to ovel
two feet of mercury, must entirely
screen these rays from lower levels;
but Alpine tourists have often reported
strange Jogging Of plates. which the,
have been disposed to attribute to thu
warmth of a guides back.-Prof. Oliver
Lodge, in London Electrician.