The Scranton tribune. [volume] (Scranton, Pa.) 1891-1910, 1896-02-28
THE ROENTGEN DISCOVERY.

THE ROENTGEN DISCOVERY.
What 1t Is, How 1t Was Made and What
1t Mcans-An Explanstion Which Can
be Understood by All.
Columns of academic discourse con-
cerning the so-called Roentgen, or Y.
rays have left many people confused
rather than instructed. 1t has re-
manned for Professor Henry Crew. of
Northwestern university, at Evanston.
ILL.,, to put the subject in a light COM
prehensible to laymen. 1T is to be
presumed" says Prof. Crew. that
everyone knows that the chief source
of popular interest in X rays lies in the
possibility of their application in va
rious arts and applied sciences. The
fact that a human hand was one of
the first objects photographed by Ro-
entgen appears to have been a some
what important factor in producing
this tide of public enthusiasm. l say
this because Lenard, at Bonn. some two
years ago, had made silhouettes with
cathode rays. and had shown that these
rays would easily pass through an
aluminium sheet placed in front of the
Photographic plate.
"In scientific circles. interest in this
discovery Of Lenard's was both wide
spread and deep. Lenard's paper was
translated into both English and
French journals of science. but the
newspapers had not Il word to say
about it. Now that everyone is read
ing whole columns about X rays, it
may be worth while to say a word
about the history of the ease and then
a word about the present status of the
case. In general 1T may be said that
the physicist finds these rays quite a
,,yrln f,,, th, St, hot l,a
does not know just where to pigeon
hole them. The combination of prop
critics which they possess is something
very novel.
VACUUM TUBES.
"a vacuum tube is one from which a
part of the gas it once contained has
been pumped out. When the 'vacua'
thus produced are moderately high, and
the tube made of fluorescent glass, the
combination is generally called a Gels
sler tube after Geisser, a skillful me-
chanic!an at Bonn. If, however. the
VaCua are pushed much higher so that
only one-mllionth, or less. of the orig
iral gas remains, the tube is called a
'CroOHes tube after the well-known
English chemist. William Crookes.
CATHODE RAYS.
Maxwell says the word cathode
was coined by F'araday ani Whewell
conjontly. II il used to describe the
end of tie wire by which The electric
current leaves the tube. IT means in
Greek "a road leading out Of If now 81
metallic object be sealed uD in one of
these Crookes tubes its shadows may
be easily seen upon that mart Of the
wal! of the tuhc cpDn@it" IT." ""t''"dr
so soon as Il high voltage current is
passed through the tube. Lac rays
which produce this shadow and which
evidently originate on the cathode are
known as cathode rays our EncWl-
edge of the existence OF these rays
and our earliest Knowledge q. their
properties Is due to Crookcs and Hit
tori
"The behavior Of this highly rare
fled matter l'Crhaps gross matter. per-
maps ethe0 was so unique that II re-
ceived special name ard has been
known for many years as 'matt2r in the
radiant condition. or. more briefly, 'ra-
diant matter 1t has been called also
the fourth state of matter to dis
tinguish it from the other three-solid,
liquid and gaseous.
\ DISCOVERY or HERTZ.
"The naxt in"ortant property OF
these rays was discovered by the la
mented Hertz in the autumn of 1891.
iiei 70 was 'nc'i professor oi physics IN
the University Of Boun. He first
showed. by experiment.. that these ca
thod" i3vs were able to pass through
sheets Of metal. thin sheets to be sure
and YET thick enough la Ge perfectly
opaque to ordinary light. This was
certainly very remarkable behavior for
particles Of matter, at lea"t for par
ticles of ordinary matter. so strange.
indeed, was this property Of cathode
u L..
GeathhloW to Clookcs' vjew--viz: tina,
these rays are streams of highly rare
fled hut ordinary matter. Hertz
thought If them - disturbances in the
ether, 1t was ShuW!. however, on the
other hand. iiIat these rays could be re-
tiected by a magnet, just as Il copper
wire conveying a current would be.
And this act led Others tn maintain the
older VicW-NiZ.: that cathode rays
were streams of matter III th- ordinary
sense.
Lt.NARD'S WORK.
"'rhe next important step vas made
by I.cnard, now at AK Ia Chapelle,
then at Bonn rs assistant to Hertz.
Lenard. Ia the latter part Of 1899. sue
ceeded in getting these cathode rays
out of the tube in which they were gen
| Grated. Their study thus became .
matter of comparative ease. i.Gnard
says 1t was at the suggestion of Heri2
| that he sealed an aluminium window
into the walls of his CroOkeS tube and
thus provided an exit for the cathode
rays. a somewhat cul.OUs window:
one perfectly air tight and perfectly
opaque to li"ht OF ali knoWu kinds.
.'i'he rays once outside, LcDard quick
ly discovered new and startling prop
critics in them. one is the fact alluded
to above. that these rays viii pass
through substances perfectly opaque
to ordinary light. and still affect the
Photographic plate.
Some substances, especially dense.
were found to he less TRANSPARENT to
cathode rays. so that one could obtain
sihouettes of these latter substances
even in daylight.
THE DISCOVERY OF ROENTGEN.
"'rhe state of the question remained
pra ctioally as described until the be-
ginning of this year. when Roentgen.
a physicist long known and highly es-
teemed in the scientific world. showed
that rays which are in very many re-
spects similar tn those which Lcnard
had studied could be observed through
out very large region roundabout an
ordinary Crookes tube. But in two
features, at least. these new rays are
quite different from cathode rays. They
are not appreciably detected by mag
net. nor are they SO readily absorbed
by air as are cathode rays.
These differences leach of them pos
sibly only differences of degree) are all
important from the practical stand
point. In the present state of ignor-
ance as to the identity of these rays
Roentgen has proposed the name "
rays
"Roentgens paper describing quite
fully his numerous experiments will be
found in Nature, Jan. 2S. 1896. 1t is a
model for any worker in science. For
Professor Roentgen has followed the
advice of Sir Philip Sidney and has
been rather doing things worthy to
bee written, then writing things fitte