New-York tribune., 1901-11-22
PHOTOGRAPHING LIGHTNING.
PROFESSOR PICKERING's EXPERIMENTS
BELIEVES HYDROGEN A COMPOUND.
Try TELEGRAPH TO THE TR,

fBY TELEGRAPH TRIBUNE
Boston, Nov. 1.-The circular Just issued by
Professor Pickering. OF Harvard Observatory. con-
tairs an account Of first successful photograph
of the spectrum of lightning flash. which will
interest scientific the world over. one or MS
assistants in July and September obtained three
photographs at a time when there was lightning
but no rain. He used the same apparatus that is
ordinarily employed in taking the spectFa OF the
star-a big S-inch I-inch telescope. with camera
at one end and prism the other the prism being
placed front of the objective lens to break
up the object photographed into parallel bands OF
color which in the photograph by differ
ences in degree OF black and white
The process by which the lightning spectrum
has thus been finally captured is not unlike that
az taking snapshot with d pocket camera. with
the important exception that the apparatus IS
larger than the photographer. When the stars are
photographed this apparatus. sometimes weighing
several tons. moves by clockwork. following the
movement Of the celestial bodies
Lightning is obviously different matter Where
the flash will only be guessed at, and the
instrument is controlled. therefore not by clock
work and electrical attachments but by the hand
of the operator. The fash itself. once II comes in
the field Of the telescope. is a automatic, or
natural flash light. The situation is further com
pIicated by the fact that the prism refracts the
lightning-that Is say, ,he lightning enters and
leaves the prism angle-ard tae telescope
must be aimed at the fash g.. io a certain
number of degrees. according to the prism in use.
TO one side Of it There Is of course possibility
OF tine exposure. and the success OF the photo
graph depends upon the good luck well as the
good judgment OF the behind the telescope.
The different photographs showed the curious
fact that the spectrum of lightning is not always
the same Some OF the photographs snow d curious
doubling OF the bright lines Of the spectrum. the
separation varying in different portions OF the
fash
Professor Pickering at first inclined to be
neve that this due another flash, in whose
spectrum only portion Of the l>aes appears-in
other words that It was sort Of composite photo
graph. but he has revised this opinion. and now
concludes that the doubling looks though hydro
gen. the only element studied in the lightning spec
and hitherto believed be least likely ever
70 be proven compound body, is made up Of at
least three cOmponents-
This conclusion Professor Pickering bases upon
the fact that there thirty lines in the hydro
gen spectrum one photograph, three in another
and third. the different flashes having been
photographed under different circumstances. From
! this experience, he says. enabled TO make
analyses OF gases under enormous pressure and
temperature conditions not attainabe the earth.
Another remarkable circumstance in connection
with The study of the Pickering spectra Of light
ming flashes Is that they similar that of the
second in the constellation Perseus, known
as Nova Persei No. % which taken Marcn