New-York tribune., 1900-11-18

0~A'NO VI d CLOCK weight Tin VaneS on
drum met with enough resistance from the air
10 retard progress adequately. Careful tests
showed that the drum not only revolved uni
formly, but that its total error WAS not QUO,
nan second during totality which lasted about
." minute by this apparatus no less than egh-
'S-'"fee exposures were made with a single
camera inside of fftyone and half seconds. a
record never before made with glass plates.
THE GLYCERINE CLOCK.
Another Of Professor Todd's innovations is a
glycerine clock" for the guidance of telo-
scope during an eclipse. He thus makes it un
necessary to convey. to the scene of action for
temporary use the costly and complicated ma
chihery usually employed in permanent observa-
tories Professor Todd mounts his telescope on
d Tripod TWO legs of which remain of uniform
length. Into the third is introduced a cylinder
anu plSton' so arranged that the latter will be
Slowly forced down into the former by the weight
of the instrument The cylinder is first filed
with glycerine, and this oozes out from d valve
at a prescribed rate, which regulates th. sub
sidence of the burden, which movement in turn
Keeps the aim of the telescope accurate during
the period Of totality. The glycerine clock is
PROFESSOR Todd's invention. but he has improved
on ms original design since first trying it. The
clock used At Tripoli was placed we'll up near
the head Of the tripod. The telescope was
mounted in the court Of the British Consulate
in that city
Before starting for North Africa last sDring
Professor Todd tried to obtain a biosrapn for
use during the eclipse. Such an instrument
would take pictures in d more rapid succession
than is possible on glass, But he was unable
10 get what he wanted. either in this country
or France, in time to do any good. The bio
graph film which he showed in Brooklyn q few
evenings ago was L copy of made by an
English astronomer, Mr.. MlskeIyne in Georgia
last May on this the photographs were taken
at the rate of nearly four second, or three
hundred during a minute and twenty seconds
The Amherst professor is very enthusiastic over
the possibilities of this device for recording phe-
nomena OF brief duration like the flash spec
trum'
NEXT YEARS TOTAL ECLIPSE
Astronomers are now looking forward with
special eagerness to the total eclipse of the sun
on May IS, next year. This will be visible
only over and near the Indian Ocean The
period of totality will last six minutes and
thirty seconds longer than that of any
solar eclipse ever scientifically Observed The
opportunity for studying the structure and
composition of the corona, the nature Of the
promlnences and other problems relating 10 the
envelopes of the sun Will be highly exceptional
1t Will be a source Of great regret If it is not
N''4'~cu ~ lht UTMOST dIU preparations for il
shouid be undertaken at the earliest possible
moment. During the last decade since Profess
sor TODD set the example, it has been Gus
tomary to organize series of weather obserya-
uohs Tor a considerable period before a total
eclipse, TO ascertain the probabilities Of a good
sky. AdVices recently from the Survey Denart-
ment of the Netherlands army in the East In
dies show that while heavy rains occur in Nav
on the island of Sumatra these do not involve
cloudy skies. but. on the other hand leave the
atmosphere in a beautifully clear condition
When Professor Todd is asked whether h., ex-
poets TO go to Sunatra next spring he answers
eNaSlVely. His plans evidently not com
plete. 1t will be remembered that before the
eclipse of 1896 d. Willis James and Arthur Cur
tls<' James. Of this city, placed their yacht at
Professor Todd's disposal. and themselves ac-
companied the Amherst expedition to Janan
Their experiences are delightfully."- recounted bv
Mrs. Mabel Loomis Todd. in Corona and Coro-
net" In like manner General Baden Powell took
some English astronomers to Nova Zembla that
year, thus making il possible TO get almost the
only significant pictures of the corona taken in
1896 Should muntcence Of this kind make it
possible for Professor Todd to visit the East
Indies next spring. and should the weather
prove satisfactory. there can be no doubt that
the study If solar physics would be materially
promoted.
EARL SPEACER'S FAMOUS SHORTHOENS.