The times dispatch. [volume] (Richmond, Va.) 1903-1914, 1907-06-09

that they would not miss flash when
one occurred. TO secure the. photo
graphs desired, the tabletop was then
revolved at "a certain speed
The results are interesting. Where
the flash appeared perpendicular, the
negatives Show naturally a broad sheet
for a mere streak of lightning. BY
calculating from the speed of the cam
era's motion and measuring the width
of the sheet, the time of the flash is
easily dcterminable. But the photo
graphs showed at the very start that
a single fiashsis not one big vibrations,
1t is made UP OF very many minor
flashes, or srushcs, following usually in
the. same channel as the first one. and
herein lies the special value Of the
work. In the best OF the negatives
there are easily counted as many as
forty separate ruslles which, as the
wholesflash lasted little over half q
second followed each other III marvel
louslyHrapid succession. Byfmeasur
ments and by subsequent calculations,
Mr.. Larsen determined the actual time
between each rush. The figures, as
may we'll be imagined, are almost in
Isconceivably SMALL varying from the
4 largest three one-hundredths Of a sec
ond to the smallest, as low as two one
Ithousandths of a second.
/
There appear many peculiarities Of
these separate rushcs which might bear
! scientific Investigation, but the most
salient feature over which meteorolo-
glsts and electrical engineers may puz-
4 Zlo is recorded on some of the plates
among all the bright oscillations as a
4 marked black rush Of lightning. The
! idea of lightning producing the eX-
! IRENE of darkness is repugnant to the
| - <,,t,, vn{ hn
| black rush Is plainly Visible. Mr. Lar
sen, after rcfuting q number Of sus-
gestions that might be made to account
i for 1t. ventures his own theory to solve
the puzzle. In discussing the record Of
a particular flash IN which the mark
OF the black rush Is very distinct, he
.Concludcs: "The flash must have given
] out light of a wavo length much
\ shorter than the wave lengths Of Visit
BILE light and with power sufficient
4 TO render the portion Of the plate
/ struck by It non-scnsitivc to ordinary
light" Such flash" he says, would
4 appear black on a partially Illuminated
background, or be invisible
Invisible lightning, therefore, seems
A to be term perfectly proper In view
Of the results recorded in some Of these
4 photographs,
At the suggestion of tho Institution
sen carried his researches still further
into the actual makeup OF lightning.
! PhotophnphS and studies OF the light
| spectrum OF electric flashes In the air
| were compared with sparkn produced
J by static machine. The conclusions,
| in line with tho ccntury-o)d ooserYa-
| tiona OF BENJAMIN Franklin. show that
| there Ia little pcfceptible difference.
| Dry Weather lightning.
l III gaIr,r ID 1 4 -
spent entirely IN waiting for thunder
storms. He has been Interested also
in atpdyng the colorcd light waves
| giTen OF by many Kinds Of substances
| nineraig and ciemicas solid ana
| (iiGuid and gaEgeg. When they arc
tf1rnaelYes subjected TO light action
| tThis IL known among men OF science
aH the fti0rfsrcncc of substance, and
speaking IN popular terms "a not very
aaneFHnt from phoaDhOrescenc In thcsc
trSestigar0ns lie tns been assistnd
difGen2 Nv the Rational Museum, whcl
| bhk mdYib~d hifG and loaned him hun.
| preds ~ specimens from III VOL fDlct
carer ~ ~" Gi3isi3a ~ gholoRy. Thu
FGs0tte Wh3eh ~ M. forwarded, ia,
Ms t'7Is"Rnl e2o9f,k, mrs Yi,aiIy !n,rr
=. SffighB ~ thE S1asEs-Bt m tlig partictiin
property NJ t8&sf@s
YiJA iahSt faeS< p94tttlea NY lhr. Lar
Eeb y ~ asfs3ae@e3SN# Ff2rtf1stion ~.
M !tkE taE&H E9aR Stss 535sf lfsi pro
pgsGs ~ 1i]afs5zs'8isR SaSHftie spark
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ada uFtts5y hsAs,ss eas@fSs stud
gf sfeNi a8E s,sS 4satar3ssig - ou
}fH9|AeaFG at fesaa5Tf ,tEf9f lsia IN
vsstiKatiaa ~ f}istgiNseo&ss, .a0 ~ III
| ttllgi - e&ttY 3ss3 &3s4a@g G@taU IL
passing IN ft@attfH sFffsiat t3lRp#is b aui
btanefs W . Yae73#tty 8a@ mskTb3nX III
fes1lts,