New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1878-04-20
ACADEMY OF SCIENCES.
PHONOGRAPH DAY.


ORs TO Mr.. EDISON, AS AN INVENTOR
IVRoM A sTAPF CORRESPONDENT OF TIE TRIBUNEI
WASHINGTON, April 1S.-The elections at
the business this morning made notable change
In its officers Professor o. c. Marsh was elected wee
president in place of Dr. WocOt Glbbs' whose Term Oh
Office had expired 1t was deemed desirable 10
have the department Of natural history fairy
rcpresented among the official heads Of the Academy
before this election they all engaged in physical or
mathematical science. On this ground DR.. Gibbs him.
se urged the change upon the Academy as wen as on
the eminent fitness OF the candidate. Professor D.
ii. c. Coffin formerly superintendent OF the Nautlca'
Almanac Bureau ard OF mathematician taxes
the place OF Professor j. T. Iigard as Home secretar
circumstance which also furthered this view. PROBES
sor Marsh being President OF the American Association
for the Advancement OF Science is now rapidly reaphg
the honoIs which have long been justly his due the
Academy, in making him Nce-PreSident' gets
as much as IL gives IN fame. Having done
90 much In the way OF election WITHIN inc
past two or three days, the members felt like resting
nom that kind OF labor. Consequently they did not
add as they were expected to, two more new members
20 make the usual yearly addition OF five There Is ~
deed narrowing suspicion among the friends OF cand
dates that the three elected yesterday are all who will
be so honored this April There are many OF the oder
members who are not at all anxious to increase the mum
Der Of academicans, and similar feeling Il apt TO DC
developed suddenly In the younger ones the day aer
they are elected
MEASURING THE VELOCITY OF LIGHT
The first essay this morning ny Professor simon
NewcOmb. on "Plans for Measuring the velocity OF
Light lie began by saying that ais communication had
reference 20 determining the problem of the solar para
Iax-the distance OF the sun Among the most elegant
Of the methods tried for this purpose was that which de-
pended upOn the speed Of light rs evident that we
knew how seconds takes light TO come from the
tu 70 the earth and II also knew how fast II moves
Ia second could at once determine the dlslLSe oI
the by multiplying the two numbers together Now
Pho NM
nn TO the earth has been pretty accurately
determined 10y two independent Notwithstanding inc
Pcpses OF Jupites satellites, and measuring tne aDcr
ration OF the fixed stars OF the two methods the acr
was preferable But the experimental problem OF md
ing how far light in second on the Carhs sur
face has proved Of extreme difficulty, owing TO us
enormous velocity Of more than 600 miles per
Two methods Of making this experiment have however
been tried; that Of fzeau win toothed %lioe, ant
that OF Foueault, with REMOVING mirror, INC eApcLr
ment of Flzeau was not entirely successful because OF
very short distance over whichhe light could travel
with the apparatus employed 81,
The problem now to he attacked is to send the light
by one mirror 20 another at or two miles distance
ana receive 10 back again on the revolving mirror iom
which il sent new method OF doing thls' or lls
equivalent is believed 10 have been devised ny an officer
I'M the Navy but this Professor Newcomb has as yet
particulars The difficulties In cfecng the object
raw 10 concaye mirror; there the chance OF catch
ing only part OF the return ray To catch the whole OF
n, Professor NewcOmb proposes 20 use second tel,
escOpe the first to be used only for sending He would
employ the electric nsnt smn d rUuga t Tu Of
Foucaut BY receiving the return ray In second
telescope IN also the great advantage that the eye
OF the observer will not he daZZed by tue outgoing raw
This arrangement has been partially tried by Professor
EewcOmb merely setting II up il concerned lie
had attempted 10 obtain the reflection OF concaye MIR
Tor the Capitol from the Observatory aud aterward
tried n between the Observatory aud the Nautical
Almanac Office; ne had fairly succeeded with eight
inch mrrora distance OF one and Onehird miles 10y
using distance OF 1000 feet If the mirror only makes
thirty turns In second, the return viii hayea deya
ton of about third OF degree Since the mirror may
he rey0vcd IN opposite directions deviation amount
ing to 40 may be measured; and there would be no
difficulty In thus obtaining accuracy within two
The great disturbances OF for the solar parallax
were alluded to. Recent British calculations from the
% Venus observations have value
the old Of Encke (Which has been generally dis
OF l. Nerricr which Is employ ed IN the British Nautical
Almanac Trere is at all events range Of more than
per cent discOrlance among the values which good au
thores consider the most probable But II the deter
minaton OF the velocity OF light can be successfully
made, the uncertainty would I've diminished to the lOOOh
part. Such determination Of the parallax would
be economical measure for the Government,
cost OF nom IS 900 to 600 While 70 send out parties
10 observe the next transit OF Venus IN 1852 VIII cost
more than 100000. The hope was expressed that
some would be ready to attempt the solution Of the
that Professors Mayer Pickering ana Barker had Deea
paying attention to the suBiec II no one else VIII un-
for the reasons mentioned IL Is expected that Com
mittee Of the National Academy VIII consider the sue,
desirable undertaking.
me TESACnY OF FIBRFs.
Professor W. 4. Norton. Of New-Hayen, delivered an
essay Force OF Effective Molecular Action The
PAPER is remarkable "a showing how a useful and
mathematical investigation. Professor Norton said
that tie ordinary conception Of moocu!c is that 1t con-
ssts Of a group Of two more atoms, each Of which
has power Of repulson for certain distance around
st, aud the molecule has power Of rePulsion for
certain distance beyond Professor NOrtOhs con.
rcptOn Of an ultimate mOecule or atom Ia that
70 Is surrounded with atmosphere OF ether which
ate on the adjoining atoms The eaScyc molecular acion
Is the difference between the airaenye anu fepHisye
Professor Norton has number OF interesting results Dy
mathematical methods OF deducu3h' Ioiinula t, nus
tenacity Of any substance. from the coeclent OF It's
elasticity. Taxing the observed tcnacity OF iron as
basis ot comparison, he has obtained lhai OF several
other substances, such teak, locust Wlte pine ana
cSStngs' lead. and even Of water The enacties thus
calculated agree quite nearly with those Observed with
Henry ON soap bubbles gave several hundred pounds
tenaelty for water perhaps that Of Ice. tnioru-
ject were burned in the fire OF the Smithsonian
Institution The curves OF the ratio OF attraction
and repulsiOn given for irOn water aud gases Nv
these the distinction may bc oreseen between
temperature aud those which caunUt. The curves
gave evidence OF the correctness Of the critical
dfews Of Avogadros law that the molecules are equ
distant IN all gases; of Boyle and Mariottes law and
also OF law prOpoundod by Professor Norton In an
essay on Contact RcpulsOn
VERTEBRATEs OF THE PTRMIAN ACT.
There were only fifteen minutes OF time left be
fore the exhibition OF Mr. EdlsOns photograph was to
begin, and the audience and adjoining Hobbies were
already crOWdcu ptOpie ahAlous u sVV Hc"i
Under such dscOuraging circumstances, Professor
4. ID. Cope called upon to deliver his
essay upon the Vertebrate Fauna Of the Permian
Period IN the United States. He explained that
Il would 80 minutes In delivery, and wished TO
postpone 10 til tue This privilege was not
c1anted he was urged to proceed with his essay, and
finally c0nsented the result being thar much confusion
arose during the delivery, and cu In two, l0lf
beng given before and half Immediately after the tele
phone exhibition Professor Cope took tho lal OF Ills
nerves aud temper gOOd-humOrcdy
Professor stated that the vertebrate fauna OF the
Tho
that had Inhabited North America The first dis
royetes Of It, species made In Germany III Thur
inpn. these wore fnnMed additions from Southeast