The Minneapolis journal. [volume] (Minneapolis, Minn.) 1888-1939, 1905-05-06
TO REPRODUCE
THE DAYLIGHT
CHEAP ILLUMINATION NOW ON
IT'S WAY TO PRACTICABILITY.
vacuum-Tube Lighting Gives Great
Promise for Future What Has Been
Accomplished, and What Remains to
Be Done-Mercury Vapor Used at
Present, but Another Vapor Is Sought

Be Done-Mercury Vapor Used at
Present, but Another vapor Is Sought
For.
Nebraska State Journal.
! According to D. McFarlan Moore in
Casters Magazine, the first CONNER
cial installations Of vacuum-tube light
ing, which initiate daylight in color and
diffusion, are now accomplished facts,
and vacuum-tube lighting is destined
comparable to that now held by other
great modern Improvements. The
problem of developing new form. Of
Illumination based upon the principle
OF using a gaseous electrical conductor
as light source says Mr.. Moore,
has commanded the attention Of the
greatest of scientists for many, years,
practical results have been extremely
meager. Probably the first vacuum
tubes were the bafemeters of the
monks of the middle ages. While be-
ing carried along dark Railways very
faint glow was detected, due to the
mercury acting on small quantities Of
! thus appears that the first electric
light was a vacuum tube, and a mer-
cury tube at that. Many years later,
about 1854, Gessler sealed platinum
| wire into each end Of small glass
tube, partially exhausted it and at
| tached the wires to an induction coil
the result, on the passage Of current,
being a feeble light, which has never
ceased to excite interest, even tho it
lasts for only a very short time. The
many difficulties in the way Of making
commercial vacuum-tube lamp have
been almost insurmountable, but if
there was any difficulty more pro
nounced than the others, it was to pro
duce light that would have COM
mercial value. More than year, how
ever, has passed, and the already men,
toned practical installation has run
continuously without any attention
whatever, and is today in exactly the
electrical and photometric measure
started.'
Mr.; Moore gives the details regard
ing the Investigations of many in re-
gard to the methods of using the
vacuum tubes, and their failures and
partial successes, and the fact that
many have endeavored to solve the
problem Of the production Of artificial
the. electrodes, in the hope that a ma
terial could be obtained which woulC
not only act as the electrode, but also
furnish the gaseous conductor, so that
! an efficient form of light would result
He tells of the lighting upon the mer
curry vapor as the medium, but de
: clares that there is very little doub
that mercury will not figure in the fna
solution Of the problem, because, un
devoid of red rays, and holds that thu
time is not far distant when direc
current, arking, vacuum tubes will b,
: made commercial, especially in short
lengths, without the use Of mercury
but with daylight spectrum.
Al A quarter OF a century ago. b.
: says, "the great problem in electrical il
a suitable flament for the incandescen
: lamp; today, it is to find the gaseou
conductor for the vacuum-tube lamp
|. 1t is purely an electro chemical prob
lem-in many respects the most i'm
!. portant of electro-chemical problems
!, and yet few professors definitely real
!, ize that there is such a problem, an
y no textbooks even mention it. Sine
= the tubes must be transparent, the
5 is fortunate that the problem is no
q complicated by the glass being acte
upon by the gaseous conductor. Of tn
thousand or more gaseous conductor
already tried, none Of those which wer
s at all hopeful had any effect on tn
!, glass. At best, the work i'm connectio
r with simply trying large numbers Q
It different gaseous conductors is grea
but it is further very much augmente
:; by the necessity Of repeating tests wit
It the same gases many times under di:
a ferent conditions, in order to determin
s thee 'ritical pressure, or degree c
q vacuum, at which each gaseous col
l. ductor operates best.
g "To be at all promising as igl
y producer, a gaseous conductor mus
Il fulfill large number of exacting col
is ditions, the most salient of which ar
IS t that it should ~, be capable of giving
" feiency, Of long life, and Of dayligl
r color values. None Of the ordinal
10 gases found in nature, either singly
in in combination, will even approxima
ae to these specifications. The gaseo,
1t conductor that is now commercial
e. fulfilling these conditions is man
st featured under special conditions and
OF OF found to be equally applicable to tub
rs in which the ionizatioh. is either pc
IL manent or intermittent. Outside Of tt
e. utilization of the discovery, vacuum
j., been able to hold their watt and lig
:. measurements absolutely constant ev,
ne for a few minutes, and the fadil
Of away Of their entire luminosity is
Oh matter Of only minutes. Therefore til
liv enormous advance over anything hel
he tofore known for this purpose; neve
ur theless it falls far short of giving t
b ,e extraordinary efficiency that thee
ny shows to be possible.
od 'sBut now that an actual CONNIE
, 4a cial start has been made, the final sol
bis tion of this great problem, as theort
ID ically Indicated, will soon be reach
, INT and we shall have artificial daylight
o ON least thirty times cheaper (not so p
lso cent cheaper-the gaseous conduct
'ch now found is about 80 per cent cheap
than the incandescent lamp) than
possible with any means known at
present time. Electric lighting "
then become the greatest of mo
IN agents by invading the novels Of
ted poorest of mankind instead Of bel
one confined, as now, only to the homes
Of the well-to-do. The solution of
eet problem necessitates the practical
600 plication of much of the intricate tn
at ry of electricity and the composite
ing Ing Of matter in general that has been
ea aS freely discussed within the last
years.
for esTube lamps of this character, es
e de. cially when operated by alternate
the currents which probably necessitate
reconciliation Of the gaseous conduc
ing ing for each alienation, should have, t
t tore oretically, life that is almost uni
.orn ita6 and a1readv practica ia hear