New-York daily tribune. [volume] (New-York [N.Y.]) 1842-1866, 1848-09-23
Sri.nfIfr Conreniion at PhiladfllhIa.
H,id q, As CgHeys Hal ef re Uaisg'iy Ni'f'-''fd'
Reported fof The Tntule.l
Third ia l- WORN 40 1-'a4'-'
r4r SECTION OF NATURAL HISTORY


THIRD DAi-NoESiNG SESSION
rHr SECTION oF NATURAL HISTORY
PHILADELPHIA. Frday Morning sept %
Borb section" Of the Convention met this
morning al .he same respective places. mere
was a large attendance AZ each.
Ia that pertaining 20 Natural Hi09rY ana Df-
of9,s the morning meeting was organized by ealing
DR. BrowSE o. the chair until The arrival Of pr. MOB
Ton the regular presiding officer y the day and ol-l
meas was commenced "
The first thing ~ order was the naper oi MI l..
Gvp,,,rx On the Causes fn Nature Qf D.srnFo1 az
r,seqrqi n Syrerfral S'rqf1 Mr German remarked
inst r IL familiar 20 every that the planes OF ine
Ter-esrisi EQUATOR and The plane ~ the Eel pc Torn
an ANGLE ~ about rs . NOV there are two motions
Of die Earth aside from the perrurha'iuus VIZ IT.
diarnsl revolution around s own axis and is annual
revolution about the Sunfact o. rhfct rf'24iYN ga
% farm flf Erri in the direction ~ their resultant
force in a ul4rc wlO-e direction u Intermediate ua-
tween the direction Of the two. operating upon i"e
cr.t OF the carta most effectively within ne Unite oi
the Torrd Zone 70 wa nv. rfsHt0Gf c0frrfg1 f.cr
10 which Sir German called particular attention as ne
substance Of biz theory Of aalienns uqneh'a- aL1 s
I5.,rt. l15 fIe,r Musical iDDqrQff e.-professor
AGAesfz gave an account Of the Structure 0ihe Phonetic
Apparatus OF Insects OF the Order OrhgpO1 partcuar
In the Crckets The Professor observed that b. bad
been Jed % these Investigators - some very nieIti
inc remarks upon the W ng OF the 1ra hopper in .f
Transactions o. the Academy Of Natural sciences oi ''
1he Wings ofthe Grasshopper have elastic spring.
hv which they are folded. when n state oi rcplfe-
prof Agqssx proceed % demonstrate fne structure pi
fbose WING. On The black board 10 bad occurred ~
him that me saHs structure might De- i9uhu DO otncf
insects lU. and lnFesu-arou Doc hdd lolnd iAl- Pop
be- the Fact The same general structure DE- common 90
an Insects OF the order OF Dthop,era ana tnal Do Dr.
DISTINGUISHING feature Of ali The varieties OF that large aud
interesting cfoupe 70 by the acton and contact OF
these tpnnes then that these insects produce Their
sOncs.
Trii0bues calling attention 90 some particular species
OF which he exhibited perfect specimen found n iAc
Bald Eagle Valley Pa. The specimens pre5entei con
tanned the body OF the Piacg1s t1psuanu 'Co'gmlr
picr0rs- Green. whereas the head and tail Oh TINS
species are the only portions hitherto discovered.
Prot HALL added some observations on the
same SUBJECT
Prot AGAs-iI then proceeded to speak of the
Comparison b.fuela I pine and NorstrH IfgcaioH-
His remarks referred principally 10 the general oOsef
vatons of Humboldt but many facts Observed On ihe
North American Continent were added in continuation
of the general principle Prof detailed the limits
and appropriate regions % various tre's Of our own
country lie remarked that they most diher nom
European species although analogous 10 general 'na
racter All the Waluut-. be observed are dl-tncilfoh
European varieties yet usually resembling them
DR.. NJ. W. DiCKf,ON presented specimens oi
the worm.tracks adgcrted 10 yesterday They eN
cited very general curiosity examination and rcmaiA
Prof Hall had similar ones from New ORR
and some from Western iocaliti'- He considered
them very interesting
Prot NJ W DIcKEsoN then proceeded with the
Report on the Sedimtni ef ne hsss'VlH hfr. Pre-
pared by himself and ANDREW bRowN AN lhe-e
Two gentlemen were appointed a COMMITTEE A. me
last meeting ui the Association 90 examine ana report
upon the appearances aud character OF he Mississippi
Deposit They now reported the result Of their mVesu
cations IN detail The facts embodied have however
in fact been collected by daily Obsers alton Tor ihe ast
eighteen years and continued without mtefmlsslon
with view 70 this ReportOr the la- TWO ycsrs Of in@t
time beginning the first OF July l-ih and ending me
OF July l-i- comprising series Of noiatons aud
calculations Al the several stages of elevation ana de-
preston Of the River while osclatng between high
and low tide. The abstract gwen below embraces
the more important features Of this very complete ana
valuable paper The whole Of IL too long Tor in-er-
ton the room that j. occupied by 70 however VAL De
found 10 De- usetully hlled.
The aggregate quantity Of water discharged by the
Mississippi Is 4-s3 500 90 go cubic ieet-eqlaI 10
5jl 2}5 Il3 cubic yards or. lOl cubic miles.
The velocity assumed for the water al the several
stages Of elevation, which constitutes an essential elc
the calculations. is not that OF the central cur
rent but the OF the lateral quantity obtained ty
| many aud repeated experiments and computations
which give mean amount Gerry stRsisy bss THAN Inc
central and which E variable under varying conditions
But ID must observed that while these sensible Var
at0n Of current exist IN the lateral expansion of the
waters In the River 10 has proved Impossible 10 detect
any apprecabe difference % velocity IN tntlf vertical
Quanfity 10 unusual thing for r0V fg frccs I'D float
dorH he deeDtS part Of me Ricr r prft0y ppptnd
GUAR arrad,caused by their buteuds being Of great.
or specific gravity than the water while their tops or
upper ends buoyant often to project as much
rs fifteen Oh twenty feet above the surface of the water
They found TO be at all times transported nth No
same rfiOciV NE surface Crrrt and while they are
thus floating in vertical position their lower ends up
proXmate the bottom closely that they often strike
the protubrances projecting thereirom BY which they
thrown down at such angles AS often 20 make their
tops disappear below the surface until they hsve sur
mounted the obstruction and when such is the case
they at once erect themselves AS before
The observations made by th. Sc gentlemen lead them
10 the conclusion that in descending aqueous hud
there 40 appreCiabc difference OF velocity n the yer
teal quantity but that IL is equally the same az op 0r
b1f0mor the reason that the superintendent pressure
urges forward the unierstraum % the point OF least
resistance with the same acceeraion Of speed "hlch
the incumbent water itself may have acquired
The Mississippi Valley i found 10 contain a superh
csl OF very little short of fourteen hundred thou
sand square miles The inquiry therefore. here sug
gesis itself What may bee the relative difference be
tween the annual quantity of water falling into this
Valley and the annual quantity discharged out OF u by
the River Mississippi Il j. found by an examination
of the Meteorological Register Of the late Dr. II Iooly
Of Nachez-thst tie mean annual quantity OF water
which falls al NaicLez is between nifty five sud nityN
inchesbut such has been taken 81 the Southern eX
tremiy OF the Valley 10 may be regarded ~ an over
estimate for Tie whole area The mean quantity U.s.
there fore assumed % be- ftytRo inches and then by
calculation Will have l69 ia geo 0oJo)J cubic feet
the quantity which falls annually 10 the whole Val
ley. which Is within fraction Of being trore ls fhc
qt1Hay ~ tla ctich Is discharged by hc h.rr.
There are bat two ways by which OH this immense
quantity Of water eau make its cscapc rom The valley
one of which is ly the course of the Rive. INTO the
Gull OF MeSico and the other ly evaporation Hence
perceive that there is but one relative pant of hi.
quantity passing o by tie River for every oer parts
which cNhacd by The atm0splsrC-or. ia other
words, - by the River, ana ll-l2 0y evaporation
Thus arrive 40 the development Of a fact Of The
most momeutous importance % the Planting Interests
OF Louisiana aud Mississippi for il VIII be- readily per
ccived that the eNhaiaons promoted The less
liable viii the lands of these Two states be o. the pfrod
cli muHdd,iDls u ne Ircr 10 may De asked by what
process expect io promote evaporation so as O.
such increase of quantity q. sensily benefit
the Planting Interests, and tlet TOO, over such vast
eNcn, Of surface Is contained iu hc expensive
that compartments the Mississippi alley The answer
that tile process has been and j. now 90 rayd STAKE
II prosecution and of that Kind which is the best cacu
lated uduce such an ercc-uamt. S. che tie crrH
g tt land, Of ttt pr- ice tsis and their consequent
exposure and aimosp here The very best promo
tiers of The eyaporstr- process OF So extensive scale
10 vii loi be- O. perceive te vast difference there
must necessarily De- n The quantity % evaporation from
surface OF country exposed 90 the action % and
winds AMI one covered with dense forest where
neither can penetrate bat WIKI difficulty.
TIE lands IN the Mssisspp. Valley are SD subject o.
this increase OF exposure. that We may na1 ard the
seri0n with safety that there IS not by twenty or TWEEN
" ave per cent much water now passes down the
Mississippi annually there was twenty ave years
$50 TINS conclusion is not arrived a. hastily but by
patient observation Of the circumstances IN connection
herewith during al that lengthy period atwhose begin
nins there We're annual foundations Of almost al the low