, 1870-04-23

Meeting OF tho National Academy oi
&r4~


oooo1' A.
---
N ectInr Of tho National Academy nj
Sciences.
.-,..
INC tnlf.eentn eem,-aunuA ,-A session OF INC sa-
eonaa nsAa2aJ u oasnss ~ neia m "nan.
in8.ol lsss ~ ta,,a, lnus ~ II u
s1e1' 1ns'es- nc Nueu ue lo'u"las noses
IRON the papefa pfeaeoIeo, ~ reported In the
wushtnston Chronicle:
NOTIONS OF xARIu ANH NOON.
Professor Simon NaWconab presented D.
per On the mean motion Of the moon, in which
he showed, by reference to oocultationA and
eclipses occurring during the present and two
preceding centuries. that no correction hlth-
erto applied to the lunar tables will mako the
observation agree with tho calculation for all
these date8, Ho concludes thst some disturb
inr eleneut exists which has not bitherto beeu
taken INTO the account, and that va must At
tribute the dlscprtlAncee to one Of the two fol-
lowing causes:
I, The mean motion Of the moon Is subject
to INEQUALITIES Of long period which ara still
entirely unknown; a,
> The motion OF The Garth on its axis, and
conseouentlv tho length OF tha dsy. is subiect
to i1rceulae changes.
The latter is startling hypothesis, and one
which every theoretical astronomer must earn
estly hope to see aisprorod; Should it be sub
motion Of the moon by tables for more no thsn
few yeats will be proved iupoeaihle, Rut, as
thn 0uestion now stands. We must attach to it
a not inconsidernble degree Of probability.
This probability ariaes r1ainly from the dits-
Guilty Of introducing into tho moons mean
longitude equations which will account for the
observations II NC suppose deviation from
the received law of crayttation. such deviation
would, I conceive, result in deviation Of
regularly progressive naturo, which il no. the
nafure Of that observed. II We attribute the
deviation to the 9mpact Of neseoEic matter,
We must suppose the moon to have encount-
cred such matter by millions Of tons II We
coufine ourselves to the Law of grayitation, we
hnre the sssuranee of HAnsou that there are
no sensible inequalities Of long period pro-
daced in any known way except those he haa
computed; Between biz computation and
those Of Delsunay,we have at least this agree
meut, that the Observed positions Of the moon
are not represented by theory. We cannot,
indeed, pronounce it Impossible thst Hanson
has overlooked some sensible terms, aud the
discord.nce we have already pointed out may
very well arise from such terms. But, when
we consider the motions Of The moon since the
publication Of Hanson's tables, We find de-
Walton from theory, which, to BAy the least, it
seems difficult to account for by any introduc-
| ton Of any periodic terms whataver.
II we attribute the apparent inequality to a
| change in the length Of the day, We must ad-
nit that between the years 1860 and 1862, the
motion Of rotation Of the earth received An
acce1er1tiye impulse, increasing it by the tWen-
ty-mil1;onth part Of itself. Such = change
| could proceed only from Il change in the ST
saneement of The matter constituting the
earth. The possibility of such An effect arising
| from, changes in the quantity Of leo accunn.
lated around tho poles has, I beliere, been
pointed out By geologists. On tho theory OF
the internal fluidity Of the earth We base get
more potent cause Of changes in the rotation
among tho parts Of the interior LIQUID. That
this houid is not in 4 stata Of rev.
is Indicated by the phenomena Of volcanoes
and earthquakes. Il We suppose genera
changes in tho arrangement Of the liquid a
lA1Ee mass moving from tho surface towArC
the centre, and mass from nearer the centre
taxing its place. tho following effects viii fol,
low
| First- A di1ninution in the velocity OF tht
| surface OF the fluid accompanied by corre
spending increase in the rotation Of the cen
tral portion The velocity Of the solid czus
will then be gradually retarded.
Second. Tho gradual transmission Of thi'
increased rotation Of tho central mAsa to th
euriace, whose motion will now be accelerated
The velocity Of rotation finally obtained vii
be greater or less than tho ordinary velocity
according ~ the radius OF gyration Of tho auit
Of position Of the parts Of the fluid.
I conclude, from this discussion, that ",
havo reason to suspect that The notion OF 70
tation OF tho ernst OF the earth is subject /.
inequalities Of IN irregular character, which
in tho prcsent state OF science, can be detect
cd only by observations Of tho moon. Thi
suspicion can bo neither confirmed nor r.
moved until We have more positive kuowledg
than Nc now hare Of the poesibIe inonualtic
which NAV be produced in tho mean motion O
the moon by tie action Of Era1itatiop,
The operation Of calculating those incquaI
L. IL
tainls within the power Of anaiysis. When i
is completely aud thoroughly done wo msy a.
certain whether the result can be made I,
represent observations. II 80, we'll: thu
length Of tho day il not variable, and the fatur
positions Of the moon can bo safely predict
ton of the moon is affected by Other cause
than the gTavltation OF the known bodies q
the solar system, or the dny is it1egu1arly var
able
The first hypothesis ia certainly oxtreuae]
improbable. since the cra.itatio1 of dista1
unluown bodies would AFFECT the earth AZ
Planets moro than the moon, while the passag
Of closer bodies could not escape detection
II, then, VIC are driven to accept the altesnat
hypothesis, no may hope that within thir:
ytsrs tho observed transits OF Venus and 3fe1
curry will afford an independent test OF its co
RICHNESS. II they agrce with the observation
Of the NOON the hypothesis will be establishet
: | II not. We shall haye added one more to IL
list Of unacrount2blc natural Phenomena
CnAS1cLoo1cAL TECr11AuTIEA
DR.. George Otis read paper on the snbiet
} Of sknll comparisons and measurements. Il
stated that during the past two years ov.
, nine hundred hunsn crania have been eollec
cd ut the Army Medical Museum. Three hui
d1td and seventy-ei1 waro acquired from Il
Smithsonian Institute, in exchange for obiee
of chronological interest contributed by med
), cal officers to tho Army Medical Museum
r | ~. al ".
tiou Of thc late Professor William Gibson, al
at auction sales in Europe, others By explor
\ tiop OF tumuli in the Mississippi Valley and
' Dakota by General Swift, Medical Director
Tickr1.1IE, and BY Acting Aesiatant Surget
+ Comfort, ut Fort Wadsworth, aud the renal
t der from medical officers OF the army static
! ed 1t tho West. Seven hund1ol NJ
j ttirtT-four of these crapia have be,
Q measured, md the general conclusions iednc,
arc thct the position Of tho foramen naegnu
i is more important race characteristic th,
9 the facial angle. That the variations IN Il
= dimensions Of crania Of individunls Of Il
Il same race and sex we're 80 great that any ge
l. in averages obtained by the examination Of
- large number Of skulls, and that the e1anaiu
= ton Of large series Of specimens is neeess
. r to determine what ostcologic41 pecuIa1iti
. have real anthloroloSicAl significance. Th
= Judging from the capacity Of the Uranium, t
u American Indians must Be assigned low
position in the human scale than has been
4 lieved heretofore. That the socaied p
= ,lstor7c sknlls from talfosn1a aud nhnoia,
u their pyshecold ehafactef: saggest views
"a vorahio to tho doctrine OF progressiFe
- yancement Of the human race IN br'
- development; that there is marked dife
>, enca between the crania found II the Nor
~ western and New England tumuh and tho
n exhu1ned IN Arkansas, Lou1elans, and OF
southern states and = ie5nsoE1es: ~ me ios1 M
"a resemble the c1ania OF the Lsquinaau1. o. !
y Lappe, and other bEperl,orean races the
" ~ ter tLoee OF the ancient inhabitants Of Mexl
~ ~ md Perm in some instances, and IN others
~ The Amer7ean Indians now ensting; me
. | tlpct1rc pecula11t1es OF the ekullS etuuu,