New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1877-10-24


vgat uncertain similar tables OF relations Tor tao s,s
tens OF Jupiter ana Uranus are furnished by Profes or
Alexander. AMI the approximations ci heoy 70 lact'
were Tor the most part ate IS rem rktoi'.
TRENORs ~ EAErn's CRUST
General Ueury L. Abbot gave an account Of bis scues
ofexprunents test tAe rate at which tremofs from
explosions are transmitted through the earth The cx-
rerinents have been conducted in sctiOn with the
vo-l, m Hailet's Point. and the proceedings OF
the United states Engineer School Of Application, at
Wilcts Point, Long Island The vibrations or uemors
PASSED throu h tht caru az Long lsAd-d drlt lorna
ton. The t~nes 81 results are elaborate ana eno" d
much higher rate Oi rausnsSO Oh ia j. Wls heretofore
conceded. The following are the CONCLUSIONS; Ia such
scutial The more violent the initial shock, tue higher
is tha rajr. This rstc dnin..hcs as tie wave
advances. For one niie thto-h dEi formation, Sc
we're shock gives velocity OF say NoGo tcct per sccouC
The rate Tor the great Hae's Point explosion Wa about
$500 feet per sec'nd lor NE ms cSht mt' "uu p uI
$500 feet per second FOR thr first tnirt en- mikes hese
evidence that cannot be stated in tubular
form. The oDseryauons are made u2nn qlantl-
IL -tances. A. yet. distinction of results between
Transmission through the earth ant through water has
been asceitau,d. The resent estimates enormously eX
coed OsC gwen by Mr. Msct, reported several years
10 theR'yal Society tle highest veoctcs tl OBTAINED
highest ~ Cereal Abbnt. Photographs of submarine
explosions were exhibit 81 at meeting Inc most lu-
poitau of this scrc, OF observations were those taken
al Hilcts Point, when $4,000 pounds OF dynamite were
s&poded roIgisf f ., hTon ,IG ms
ton they had been determined by The L. :; Coast
Survey No error oi observation e0uid rTplan The dis
cIepancA between these result ana those OF MI Male
TIE COMPARISON OF COLOEs.
Professor O. y. Rood presented two essays this sub
iact They were entitled a Construction for the study
Of the Contrast Of Colors,' aud The Phot0metrc Com
parson Of tie Light Of Different Coors" He stated that
the theory Of The effect Of supervising mixing cOlors
ia to'erably well understood. few Illustrations Of this
theory were given But IN each OF reason
Ing is required 70 determine ~ advance what VIII he the
erect tn, 10y means OF pair OF diagrams, one
Of which is movable They are conccntric. Each Is
trrt
brue SO arranged that those which contrast most
opposite each Otei lAore Mhch are most ailke are
nearest together The spaces wAca are occupied by the
& rJ .tier tlch Investigation ON the mart of
PROFESSOR Rood Inc diagram cards are simply copies OF
MS scale To ascertain The result Of mixing any cOOrs
II il olv necessary slide card around IT'S centre
over Inc other iii the point Of mixture il reached the
result can DC read of, measured and estimated
The mixtures that have been thus tested are those which
are wel-EnOwu in the experience OF practical art and
the agreement OF the results by diagrams, with
these OF practice, Is WEOy Conclusive as 10 the
correctness Oh In method.
Eearly all attempts a. comparing the relative bright
ness Of cOiOIs have proved unsatisfactory. PROFESSOR
Rood tried over again many Of the experiments OF otner
myestisators When To- came 20 re Gsed oy numsTi-
Cal results they Nile 80 greatly from oD'0s Idct th~
no dependence could be placed upon them. These
various experiments were described IN detail. Finally,
Professor ROOD adopted Methon ~Aich gave much
closer conclusions A c.iculr revolving card was
used. strip Of TIE color to be- examined was
apOed all over the surface Of the card except circle ia
the center Tic inner circle was tncn painted black. On
ne inner circle segment OF wBlie was diXed The
card then reyolyed ana presented Al outer ring Of
n Given color and an inner circle OF gray lie intensity
a Al
ment. ~ increasing the size Of the segment point
was reached where the intensity 81 th gray seemed 10
equal tue intensity OF the ring " outside color. TAen
an excess OF white segment was used, and grad
ualy dnniu she'd until again tie ineusites OF the inner
circle and outer ring seemed 10 correspond. The mean
,Diut belweeu these two Oetermnat assumed
nat al which toe iuteustcs were actually equal. These
rcsuifg were highly satisfactory Among other c0nse-
o noes proof furnished FOR proposition that
rs BithrO been only regarded as improved but proba
ne IA J.. known GIasslndn's second proposition.
snCss thus phfasei: "The total luminosity OF the
1xiurc o to coiOred lights il equa 10 the sum OF tue
fVg0
fsr fIiicards inquiry Professor Rood said that IN tins
translato1 " the rule from the German, he did not
mean % make distinction between the term Iumiu-
osltv and intensity" Having fixed the luminosity
NJ series of disks OF different cOof Il becomes easy 20
compare thst Of any mixtures " coiOls
InK INNER SATELLITE OF MARS.
Professor Alexander said that when the RAPID motion
of the inner satellite OF Mars announced lie had felt
moved 10 inquire how it had obtained its great angular
velocity with this view, he investigated the orbits OF
several comets that had come near the orbit Of Mars 10
ASCERTAIN whether portion OF their materials might
have formed the satellite, Judging from their
.s,oci,,e. INC mathematical process OF coupaI-
, - shown on the blackboard, the form
r. moi being very intricate But after care
W" dnorsOu OF several comets, ne iopud noue thai
..m.wered the requirements Of the problem lie then
,rred ms attention " the asterolda Orbits Iahihg
sae of these at their peTheoD he found IL 1uy within
ps.ipty that ssterod might pas w near TIE orn1 "