New-York daily tribune., 1858-08-04

pe.ise views Of tie conduct Of tbs electric All.
in the ocesu. Both views are d,-,s,.,,
us.semstcly. By impesrs arrays f6sur., al
% -. ~ "a,
'' Dr. aT sr 4, d,
70 an ip.e rni.nsble snd terrible length No.,;,.
iupre.ses rs with so much ave a. these r,a,.. J;
bercsypsics; ro.hing is go Puzziirs .. tue Ls,r,,,
c,.sr seLtencss Of Z, elish aud tae Eups.u s.,,
ne,s Of slgebrNc 70 Tmalsries; no:airs can be u,r
lsusaabie ,r more despair provoking tha coaas
between TIE Astronomer Roysl AiT snd Win,
G,ayat..F.R s., F.R.A S. Figure. c.cac.E
We are told. Ms.hemstciaus pride their ssies
uptn beirg tie sole exsct Three or four ZEN
ago. Archdeacon Pratt, in magCihcelt pss
which be read before the Royal Society, proved y
n usthers.ics infallibe az Holy Writ, that tSe ess
uby the plumb,bobs Of the British easasso
messuIirg an arc of meridian across the n,
of the Gsrges, did not hang qa'te p'ssA
was rot 20 much the ffownirg mass OF the Hal
lsyas TO the north ss an e'liphc,ty OF the eara II
greater ,hsn has been supposed. The Assnnssx
Roy too his figures up AID proved that the esla
wss much simpler one, lyiog at tho roots Of IN
mountains; that 10 to say, not in the heavy pstsx
of Thibet, but na light plateau under ground. or
rather under crust, projected downward " I'd
and hoa'irg buoyant in the central lava bat ts,s
pressed down below the level Of the rest Of h,
earth rird BY the enormous upper load it hsi h
os,ry. And now, when the Astronomer RoJiLs
demonstrated By fifteen psses of iu'esrstou Aa
the Atlantic cable is catepsry curve settling strEs
downward TO the bottom Of the ocean, slSsys uadn
strsp, Mr. Grayatt demonstrates the exact cpa
tiary, with merely three pages OF alsesn sN,
lcearitbm OF tive proving that 1t rildes doxsa
inclined plane Of water backward and w1aa
tine snd beauty by mskicg an in6ute series OfsaL
seneical coils a. the bottom where it touches
Setting aside however, the pleasure Of thiam
contfe of acute minds over slate and pscelh
settle how the great serpent thoussrd ml1a
,hsll b. have as it crawls over the stsrns Of tAsM
sgara and AgsnemDoD, and buries its folds sulh
ny.teries of wre and Lightning six thOu,m
fathoms deep in the sediment of thousand shsm
there is left plenty to interest the lees! msth;m1k
cal reader in these papers.
The Astronomer Royal sends from GtseawicA.
June lG, 1853, three sue ;essye iuvestisstcna.
First, the shspe Of the curve when the sesb'tton
is level, the ships motion and the cabs's delycT
both uniform, and the curve taken by the abb
from sbps stern to ocean-bsd always the nua
On the suppositon that the ship moves just Mhx
ss the cable is delivered, he obtains this sinsds
RESULT" That the form Of the travelling curves
exactly the same with that Of rope stIetched
both ends, and bears the same sort ard desrssd
strain. But there was an element Intentionally
omitted. Taking ito tee account sse frehotd
resistance he finds after serie. of repulsive eqA
,lcDs," ending in the une Ipected birth Of 90 MynP
tote, that this preyiousy-foadd chsinea"
stretches itself out to nesrly straight llle toWh
its upper end with long, fiat slant upder water hl'
hat of t,w. line when allowed to drag. Whs
he cable is delivered exactly as fast as tho ZIP
sails, end when the strain at the pla.e where it
touches the bottom is o. then the cable 10 stntss
lne inclined 10 the horiz IN at a low angle ~
ship goes fast and at high arsle il "
goes slow. He then examines the amount
Of tension which the cable must endure sa
frds that it is lea.t when the ship stands stI and
the cable hangs plumb down to the bottom; va
that it is the greatest possible when the caos"
delivered with the least speed p,ssble' thH u
drsgged through the water u nearly at the spese
Of the slip as possible. The tension a'mh'a'.
by increasing the rate Of it, delivery. 10 AVON
tie stray" or waste Of the cable, 0"
its irregular winding and waving 10 tho ocean ~
fore it settles to the bottom, and yet % di~i'.
tie stain on it which alone can keep It pulled ."
straight is the great problem of the exPsnueog
ard be settles it by saying that this is sccompu'ss
more perfectly when the ship is moving GsDe
speed than at q low one.
Mr. Gravatt starts with the understs snding tA%
when ship and cable part company at tho ssms "
locty, the brakiog stain on the cable must be -"
equal to the weight IN water Of so much OF y"
would hang plumb down and touch the bottom
Therefore it will behave as if on an inclined pss
IN water. The bottom particle will feel no ssrsA
and the whole cable wi sink straight down, ~
lie without strain along its bed. Taking tho g's&
,st depth at two thousand fatboms, we hare bs
thousand pounds for the strain on the cable, SSst
ever be the velocity of the shp, or four tenta'
what 10 known to be its strength (four and s@
tuns, or Line thousand fise hundred pouudsl 0''
if the cable be paid out faster than the 'Ap
e1es, it must clip backward down this Ioc''
plane, and relieve the strain 10 that extent. sdpp1
sn angle Of twenty d'grees, and rate Of four ~
eight tenths lnots per hour, and suppose the p""
out goes on at twice that rate the total 'hPp'0s~
si.tance will be one thousand one hundred sna WY
eight pounds, aud therefore the strain uPo'
cable is reduced to two thousand eight han1.
and thirty two pouLds. But in reducing tue W..
on ,ke cable only one fourth. the DAY cut or low