New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1873-08-25
SCIENCE AT PORTLAND.


ON RAINY DAY-SAFETY IN NAVIGATION, AND
PROF. PEIRCE's VIEWS THEREON - THE OAR
wINIAN THEoRY-sUDDEN INTERRUPTION OF AN
EXCITING DEBATE.
(FRoN THE SPECIAL CORRESPONDENT OF THE rRiBuSh1
PORTLAND, Aug 22.-This was a rainy day
raw and isagreeable But there no lack OF interest
among the members of the Association nor may auu
among citizens Of Portland The latter IN iao' w
themselves special credit the ladies OF Portahu po
yded bountiful lunch for the Association and waited
on tho tables themselves The town is full OF county
people drawn together by the annual muster VI '"o
Maine militia Oldasbioned wagons, drawn oy noise'
that have seen service at the pow' carry through ~
streets beyes of brown checked lasses. with goody
show OF older members OF families. Sometimes home'
spnn clad figure looks in upon the scientific fok but Tor
the most mart the strangers who huger about the doors
of the sections and not understanding what is said
aaunter away are dressed in their Sunday clothes
Those who had studied the programme OF the day ana
who reccolected the faculty which Prof. Swallow OF
Missouri had a previous occasion exhibited for
"settng people by the ears" recognized in the an
nOunceuent Of his paper on the Origin OF Species the
prelude to lively debate. But the day wore away
with the reading of papers 1t became evident that this
one was be the last And while there good at
tendance all day both sections ii very evident
that elimination of popular interest toward the
close Of the afternoon meeting.
One Of the most valuable papers read in yesterdays
meeting was that OF Gen. j. g. Barnard am unable by
days delay present better abstract Of than would
have been possible yesterday
THE RELATION INTERNAL FLUIDIrY TO
CEssIoS OF THE EQUINoXEs-BY GEN. j. G. BARNARD.
Prior 10 the Investigations by Sir WIN. Thomson
corning the earhs rgidity, and his determination OF
the degree of rigidy needed in order that the actua
procession should correspond nearly 1t does TO the
calculated procession for perfectly gd homogeneous
spherod. the earth, the thin solid crust OF
the geoogsts had in researches concerning procession
regarded
rather it had been taken for granted
that the solid earth. or the solid crust. however
thin. practically rigid enough TO be con-
sidered perfectly rigid Hence the famous inves ugaon
the late Prof WIN. Hopkins of Cambridge, in which
treating the sohded portion of the earth as rgic 1t
was attempted to find the phenomenon of procession
test Of The question of internal fuidity, and de-
termination of a minimum thickness admissible. In
the treatment of this difficult problem by Prof Hopkins
there of the higher analysis and skill in
Its application to ply steal problems which extOrs al
miratiOn and yet there is in the faacy OF tho final
result and the general acceptance with which it has
been received that which gives the inves cation claim
TO be ranked among the " ouriOsities" of modern
mathematics. Although the discrepancy (one-seventhi
really forms the basis OF his practical application is
however believed 10 be very minute lowing TO TIE less
the demand for rigidty demonstrated by Sir VIM Thorn
son puts ont Of eonT the question Oh INN crust yet
ldent OF the Academy OF Scences) has attempted
"a
glass gioDe zen inches IN uaheter cQutanlng wafer oy
which he would demonstrate that the neglected prop
erty OF yiscOsty" Of fluid by Prof Hopkins yitiaes
s his results The late Archdeacon Pratt the other
hand. authority the Figure of the Earth" at
tempts to vndicate Prof. Hopkins Although neither
the efutation the vndcatiOn believed TO be
the other they show that the problem has not by any
lost its interest Papers read before the Ameri
Academy of Sciences, and published among the
Smithsonian contributions 10 knowledge referred
for the proof by the author that the centrifugal
force OF durnal rotation OF the tidal protuberances de-
veOped in q wholly fluid spheroid exactly neutraze the
attraction winch causes the protuberance hence that
In such spheroid there would he procession. Pari
rdOne, 10 extent protuDeTances developed in
sold spherOd, In the thin crust n the latter
nearly great wholly fluid, will the procession
neutrazed That such prOtuberances be not developed
Sir VIM Thomson demonstrates that the rigidty of the
earth's substances must greatly exceed the actual
rgdity of iron depths Of 1000 1000 miles Or the
other hand all Heterogeneous mixed liquids in CONCEAL
ing separate. Observation shows that this law obtains
In volcanic lavas. Hence regarding the earth
geaed spherOid once liquid there would be large sub
terrauean cavities still containing uGcongealed liquid
BY reference to these, Sir VIM Thomson believes that
heayals. &C.. may be explained
The paper the rationale of the action and
reaction between internal fluid and enyelopiug
shell Tor erus ana 1t very elegantly treated by Prof
that for SOmoseneOusHess Of shell fluid, procession
will be the as II the whole solid. 1t shows
erogeneousness shell aud uid-that u.s. to the case Of
the actual earth tnat Prof Hopkins's famous result
that there must be solid crust TO "a depth " at least
to 1000 miles founded upon his falacous manner
of computing the pressure OF HETEROGENEOUS enyel-
Oped fluid upon its envelope; that this determiI alton
containing all The difficulties Of the transcendental
problem heterogeneous
made by Prof Hopkins extraordinary for its faa-
ciOusness for it's SIMPLICITY by Indignation
the attractive forces on the elementary particles of the
Gen Barnard solves the question by this proposition
and asserts that It's denial would carried TO its legitimate
consequences involve violation OF the law OF cOnversa-
ton OF energy" Given Heterogeneous fluid wholly
hbrum assumed in relation internal forces and Tor
eign attraction the pressurecouple Of the hud the
shell due TO this attraction is and the that
which would be exerted on the fluid soiidifed
According Prof. Hopkins, this Identity exists
nd
hence only his famous and falacious result that pre-
cession is different for Heterogeneous shell and
fluid from that which would belong TO the spheroid
wholly sOlidhed and that there be 500
Gen. Barnard shows that this simple correction con-
verts Prof Hopkinss formula into exhibiting iden-
ty OF procession in the two cases he shows moreover
that his actual formula 1t STANDS expresses exactly
reverse from what ne snPposes; that Il really gives
thlokening the crust.
The following conclusions" quoted from Gen Bar
nards Smithsonian paper are deduced
First: The analysis OF Prof. Hopkins, in its applica
ton to homogeneous fluid aud SHE'LL to estab
fish land the result Is confirmed by its harmony with
tidal phenomena developed in 49, that the rotation
acts upon the shell II it were solid mass while its
pressure mparts to the shell the requisite couple to pre-
serve the procession unchanged.
Second The practical rigidity is, with entire
reason attributed TO the Heterogeneous by which
QeaVng OF view minute relative oscillations which
affect the mean resultant in other natural phe
and should not IN this the shell and fluid
Third The two masses retaining their CONGREGATIONS
mutual relations, and rotary velocites essentially
altered by the hypothesis of internal huidy, would
be violation OF fundamental mechanical principles
were the resulting procession not identical with that
due 10 the entire mass considered as solid.
Fourth. The common and identical procession of fluid
and shell resulting from the analysis is indispensable
10 any conception Of procession for the earth
posed thin shell and fluid; for otherwise internal
equilibrium would be destroyed and the figure the
earth to have any assignabe expression. The
entire mass fluid and solid, must without invoking the
aid OF viscosy % be carried along in the
motion OF the earth. The analysis have examined
demonstrates the possibility and exhibits the rationale
OF such community OF procession but fails In the at
tempt exhibit test OF the existence absence OF in
Inn