New-York tribune., 1896-02-06
DR. PUPlN'S EXPERIMENTS.
FURTHER TESTS AT COLUMBIA COLLEuf'
,,opr p,,orocp.pus OBTAINED WITHOUT ELEC-
TRopEs-LooKING FOR SCIENTIFIC PRiN-
rrpr rc NOT FOR SENSATIONAL, EXPECTS

reonrs-IooKING FOR SCIENTIFIC PRIN-
crpr.Es. NOT FOR SENSATIONAL EFFECTS
SOME OF THE DOCTORS OPINIONS
DR. NJ l. Pupin. Of Columbia College whose unique
achievement IN photography with invisible radiance
on Tuesday evening was mentioned exclusively IN
The Tribune yesterday morning. received many con-
gratulations during the day from his professional
associates and scientific friends. 1t had long been
known that luminous effects could be obtained IN
vacuum tubes without electrodes but 1t had been
assumed, from the current accounts OF Rontgens :
work that the unseen X rays. which exert a chem
ical influence on the sensitive films of photo
graphic plate. and which so easily penetrate SUBJ
stances Opaque to ordinary light. could be developed
only with tubes of Crooles's design, that Is. having
the metallic terminals of the electric circuit reaching
inside. Or. Pupn has entertained a suspicion to
this effect fo several days, II not for weeks and he
attempted to get a picture in this way last Satur-
day Doubtless he would have succeeded at that
time had he exposed his plates long enough. AT
that time however his attention was distracted
by the difficulties incident to cxhaust!ng large
Crookes tube and he did press the investigation
then.
Further experiments were made yesterday in the
same direction. Curously enough. the doctor was
able 10 find. over In the museum OF the School of
Mines yesterday three of four Crookes tubes. small
in size ana made for the illustration of different
scientific principles from those involved In his pres
ent inquiries These from six to eight inches
long, an inch and a half in diameter and tapered to
q point at each end. Electrodes had been carefully
inserted and sealed into the ends and the negative
terminal or cathode extended nearly TO the centre
Of the tube where IT supported bit of some kind of
mineral. The positive terminal tor anode) was IN
exceedingly modest little plate OF platinum. smaller
than the end of a lead pencil. and within quarter
of inch of the point at which It's supporting wire
pierced the glass
ALMOST ENTIRELY WITH THE Tt'BES.
The doctors work yesterday was conducted al
most entirely with these tubes. lie excited them.
however, for most Of his tests were by connecting
his electric wires not to the eecrodes but to sheets
OF tnfoi wrapped around the exterior OF the tubes
near the ends. For practical purposes. therefore
they were as completely devoid OF electrodes the
tube used on Tuesday evening ard again in service
yesterday.
AT one time the current was divided to
cite three tubes at time. bat at another only
single tube was used. In every case the slender.
fragile objects were arranged horizontally ifom
three TO six inches above the table. The photo
graphic plates were inclosed In platehoders whose
covers were not removed. and lay Nat on the table
directly under the tubes Then the objects photo
graphed were laid on the covers OF the holders
some OF which were Of ebonite or hard rubber. ana
some of which were OF wood The agent which
acted chemically on the inclosed films pro-
Ceeled, therefore, from llr Slv'N 'l Il ''''f "''
from its end 1t went through the covers without
ary difficulty but encountered dforen; degrees OF
resistance from tho objects tested An aluminium
cigarette case 60 easily pcnctrabe as - cast
on.y a faint shadow. but nails concealed IN II pro-
duced a denser \ silver haf-dollhr ana n
matchbox Of the same material proved almost as
opaaue as a brass tray asteel scrfewdr!ver and
pocket knife. Aluminium medals. a ladys "atch
and some other objects were also photographed.
but without much detail \ human hand was also
exposed two or three times. and one fairly good I'M
preston was obtained
During the progress Of these experiments. whie
the current was turned or. the tubes were hHr1
with beautiful nuorcsccnt light, either bundle ~
tremulous sireamcrs or Uniform. struciur'I'ss
glow; of pale violet or lieht-grcen hue. hut while
this served TO some extent. az an index "i th'
stua,ion the actnlc effect. of course, was produced
By something which it IS impossible to see
DR. Pupin is not seeking 10 produce beautiful or
sensational pictures but ia studying the conditions
under which the Y rays can be most aivantaeeousIy
generated ard handled and s seeking 70 simplify
the apparatus employed. The hcadway which he
has already made encourage tho hope thai he WIZ
do stin more before he gets through
A TALK WITH THE DOCTOR
After sus2enilng operations in his laboratory yes
,erday Dr Pupn obligingy talked at som" IenF'h
IN regard to Professor R6n;gen's experiments ana
the propertics Of the vacuum tube. 10 whlch Wuch
SPACE hes been devoted In several recent issues %
The Tribune Dr. Pup!n sad that Professor h"h'-
gems discovery had created an enormous sei's"'"'
no, only in wha, he called the popular world. but
also in the scientific community, on account OF 'h'
bearing which the discovery hal upon some ~ the
mos, welglty questions IN the science Of physics
about the ether The sensation produced by the
discovery he said. was even more intense tlhn ut
sensation produced by Professor Hertzs electrical
dscSys5,Tss 1s rnP he ysbS caiSoi srcam
rays have been known for long timc' ana 81 hasf
been investigated BY numerous physlen.s !" iH. ~, "a
fifty years among whom ne men,oncd
pucker end G9as ten e; rnga5I IN GGi4"'' anu
Continuing. Dr Pupin said: The theory which
Crookes formulated regarding the catnode @ys was
that they represented projected particles OF Whlt.r
moving In straight lines with enormous V,.oc.ty
from the cathode ana these pnr,lcgsi Imp p'"ths T
most recent researches n Germany! however, l"N",
different heory 1t has Peth h iouns th" ,he
streamors will pass right through them Practically
& ns IN inIasijea,jons he object OF witch was to
extend the discoveries OF Hertz and Lenard."
Speaking Of his own experiments. DE- Pupin SAID:
lad been able to obtain a Crookes tube In this
city (by the aid Of which Professor Tro"bridsc. o;
their pctures) should have produced one o, these
photorrnDhs three wee ks ago, and to Columbia
The rst institution succcssivey 70 experiment with
cathode rays In this country. Bui as vas com
nv own apparatus. sought In some way 70 modify
the methods hitherto employed ana as IN" Tribune
fully lescrb1l the results OF my s'--
terday is unnecessary for to repeat the details
of my operation.
CURRENTS WEAK
! 81 may say however. that the currents which !
employed were weak and that the vacuum WAS poor.
/ The photograph which obtained was the first one
produced in this city. and. far know. the first
/ one secured anywhere In that manner. 1t is not n
very clear picture but Is important in the respect
the novelty of the methods called into play, showing
that n very high vacuum and very high electric
AnQfnn hN IN
production OF these photographs and OF radiant
energy II Is in all probability the first experiment
! IN which E6ntgen's rays have been produced with
out electrodes.
! considering that in these experiments cleo
trodcs used and that no distinct cathode
sreamers produced. 1t H. evident that athodo
rays of themselves have little to do with this photo