Richmond dispatch. [volume] (Richmond, Va.) 1884-1903, 1884-11-29
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r A wsshinrton letter says; Professor
Simon NewcoDc, Superintendent OF tbc
United States Nautical Almanac, whose
discoveries Of new problems aud sormnias
ia mathematics and progressive laoors W
astronomy have gwen ban woriu-wlde
renown among the savarss OF this Day, mas
jus; added most valuable Contribution 70
ibe realms of science In eeriain cxpe'i-
mepts In The transmission OF iisht ana
mearurtment oi rs velocity.
Professor yewcomb, in conversation on
the subject, said: "Tbese experiments
were made between The top OF the wash
,nrton monument. which. sou know, isthe
birtc.t elevation in the District Of ColDn-
bia. and therefore freed from any obstruc-
,ion wbateytF. aud Fort Myer and toe
Naval Observatory. The latter scrfes were
nys.,ica,ly useless. but the former were
rreat success and give the actual measure.
msrts OF the yo,ocieiy 81 light on larger
scale nv the means employed than ever an-
derfakin. The method adopted was
phototacbomeier. in which applied by
new device an old principle"
hat is the method you mention? ?"
"The result Is accomplished by reilec-
tiops or flashes of iizht from a revolving
mirror making two hundred and fifty turns
a second. The distance from the monu.
ment TO Fort Myer ls 3,121.23 metres, or
nearly LOCO Yards, aud by this means we
measured the time Of passage which was a
little Icss than one forty-thousandth part
OF o 5, eond going and coming. The velo-
city ef light was measured by Nicholson.
OF the navy. over space OF about GOO
metres, and in Europe over longer dls-
tapcss. but by less accurate methods. In
our recent experiments DO not think that
the error can be more than aten-tbousandth
part OF the whole result, or one ten-thou-
sapdth part Of one Iorty-thousandth OF a
second-i in other words, about one four
hundred. millionth part OF second, IL yon
can eompreheDd that infinitesimally small
space Of time"
.What will Dc the practical application
OF these resuIts?"
1.-The chief object" said the Professor,
"is 10 measure the sun. hope 10 reach
bv this means more accurate results than
sny we have yet achieved from the transit
Of Venus. Fifty years ago the sun was
computed at 9j, 600, 900 miles from the earth.
Fifteen years ago II was estimated at
81 .O00. 600 miles. Now scientific calculr-
tons, based on the most recent data, put 10
at o2,g69.0 miles. As the result Of the
N'WCHy VI hSht "'',' "tN'' "N"'"'V W
can get the mass Of the earth, and cal
eulate within the scope OF finite
methods Of computation the Inagni-
tude OF the whole solar system which in
turn has IFS bearing on astronomical
tables and furnishes commerce with tables
for the nautical almanac, which enables the
navigator to compute his latitude and lou
eitudc on the sea and the astronomer and
surveyor on the land. 1t would change
The accuracy Of certain numbers In our
tables and would bring astronomy more
empbaticaily within fhe range Of exact
science. The results OF these experiments
will be shortly published in report OF one
hundred pages, with seven plates. and will
then be placed within reach OF astronomers
and Others interested in the United States.
Europe, or any other part Of the globe"