, 1874-02-20

Tho Foucault pendulum experiment., by which
Ia practically demonstrated tho truth Of
The Insertion, nTho world moves" was por-
formed yesterday afternoon in the Exposition
Building under tho auspices Of tho Chicngo
Acade,uy of Sciences. as tic facilities for Wit
noesing tho experiment tadyautageouslyw would not
admit Of largo crowd Of iookors-on, tho jnvita-
tion-]iHt was scomparatyely limited and as the &C.
casiou WIS ono OF uncommon intorest, thoHo who
wero favored with cards numorously ayallod
themselves of:the opportunity. Yesterdays inyi-
tations were restricted to nembors Of tho Acad.
cmy. tue Mayor, aud Commissioners OF tho Board
Of Public Workn the Board OF Education, the
FREQ Library Board, tho President and officers
of tho Board OF Trade, aud few other promt-
mont citizons, among them Dr.. Burroughs, OF
The Chicago University, and l,B friend DIR.
EyertB. The State Warehouse Commissioners
were also invited, but, as tlioy were ongngod in
looking over Iuapcctor narpor'a accounts, they
did not attend. Very many ladies' honored the
lively interest in tie experiment. Tie pendulum
mud itB relation to tue rotation OF tho earth
upon ita axis were 30 fully described aud Illus
trated in yesterdays issue Of IKE TRIBUNE AZ to
require no repetition. 1t, however, shows tho
wonderful results Of the science of mathematics
when properly applied, that the theory and calcu-
1ations eot forth in TIE TRIBUNE wore verified
with absolute precision by the practical workings
of the experiment. Mr. EtiAB Colbert anu Dr.
Norman Bridge assumed charge Of tho operation
Of tho pendulum, which had been constructed
under tho supervision Of n1r. Colbert and ut tic
oxponHo Of Mr. T. W, Blatchfora. At ! o'clock
III the afternoon tile lend ball ut tho lower end
OF tho wire was liberated by burning the cord
which sccured It at one ond Of tho wooden rail-
iug. 1t Bwung for two hours and q half, aud was
thon stopped, having doviated thirty degrees
At 3:4I by which time the. visitors had arrived in
goouly numbers, tho pendulum was agaln Bot in
motion, and swung for thirty minutes, and a07
timos, showing q 1eyintion Of five degrees and
one minute. Tho truth OF the assertion
that the course of tho ball would not be
varied by turning It around from side
to ride, was practically demonstrated, aud
M explanation Of tho workings Of the expert
mont was given by Mr. Colbert, who with much
patience and politcneHs, as well al thorough
eciontito knowledge, answered questions a'moal
without number. lie ntateti, among otle,
things, that tho anglo described By two lines OF
ono milo each, starting from tho saIno point,
and throo inches apart at tho base, was as noar-
" az could be calculated, tho angle Of the deyia-
ton OF cAch swing Of tho pendulum; and alAu
that tho deyiatons would bo in exactly opposite
directions il tho rodulum woro located at cor.
responding distance south Of tho equator. Tho
experiment waH III GYory respect successful and
satisfactory, aud reflects great credit upon the
gcnttcmou who wero responsible for ita per.
formanco. twill be repeated tomorrow for the
benefit Of the faculty aud studontA ol tho various
colleges ut later day. Tor the teacllerH Of the
Public Schools, and tho pupils Of tho High
School and still lator, for tile public in geuor.
al whom al admission fee will bo charged.