New-York tribune., 1870-08-26
MODERN SCIENCE.
THE LIMIT OF VISIBLE MAGNITuDE-THE TEN
PERATURE OF THIS CITY-THE MANUFACTURE
OF ICF-ADJOURNMENT.

THE LIMIT OF VISIBLE MAGNIruDE-THE TEN
PERATURE OF THIS CITf-THE hANufACIohb
OF ICE-ADJOURNMENT.
Tpoy. Aup. 24.-The general session This
morning gave unmistaabe evidence Of the approaching
adjournment OF the Convention. The members whose
paper have been disposed OF In the earlier DAYS OF the
session left town yesterday In great numbers ana TINS
morning not more than half the members were IN at
tendance. The most important papers OF tne CLOSING
hours may be briefly summarized paper ON the pos
sibty Of limit Of visible magnitude anofdeu Dr'
Barnard OF New York an opportunity TO explain the IN
teresting law of the imltiby in the nature Oh .nsS
20 the visibility of objects Of whatever degrees OF
meas Early in the century Fraunhoier asserted tna' ho
object of which the linear dimensions are ees 'n 'no
undulations of light possibly be maze visible ny any
optical contryance. This detum has never peeh enai
| lenged. ,...,,-
The truth Of the minimum Visibility Is uhdiVei"'i!
proyen when glass is examined by an optlcai
(perfected hy the speaker on which but pam Posn
detected and vet the polished surface of the glass; as is
well known is nothing but furrowed surface, anu tho
furrous are as real as those plowed held 10
this IL NAV be argued that object when reduced 10 tnat
degree OF minueness is Opaque ana Wheh so minute o
contrast between the illuminated part ana the other
too faint 10 detected and we do not discriminate DC
tween the dark and the light parts Of the hed' simply
because the power Of vision not sufficient and Tor the
same reason stars cannot be in the daytime III,
therefore these could be made perfectly Opaque
so as TO stop the light instead of transmitting H. s
highly probable that the lines upon the pohshed glass
could be seen by the naked eye, by the optical In
strument Objects cannot be by transmitted hght
then they must by light that is reflected dpdy
from the direction in which the illuminated light falls
Finally, there is no physical limitation TO the range OF
study declared the Doctor who the country
| over is accepted authority Oh the subject.
An examination of the temperature OF NewYork City
for 25 years were given by Prof o. W. Motifs OF the
Cooper Union the most marked point OF which was TO
prove that the popular and prevalent impression that
our climate is growing colder is totally untrue The
average temperature shown for 25 years Is 69s de
below the nominal average the next 10 years above
the three last below, 1868 being the lowest or 4Soos de
grees The average quantity OF water from ram ana
melted snowis 1865 inches During Is Of the 2b years
was above the mean and during 10 below G be gea, ~
quantity was in 1863 being 6iOO nches tne east IN
ls45 $3.50 inches and the average quantity month,
or snow fell in one wear was is9 days The largest
ber of days in one year was 10 Id 1902 ihe smaes ~
every known climacteric change and was Impressive
only for its marvellous covering of detail M ,soo.,o
Prof Waling of Pennsylvania wished the Association
to take cognzance of discovery OF the powers OF ammo
Subject the substance being that ammonia has a solvent
power certain metals, as was proved by actually
presented ali the characteristics solution, which,
after evaporation, restored to the metallic state in
been effected Experiments in connection with these
views had demonstrated that ammonia is not the only
solvent Of metals, and that other metals could De dis
solved in ammonia.
| Prof. Vanderweyde or New-1orR read a paper peru
nent to the great need of NewYork just now as well as
scientifically important" Manufacture OF Ice by Me-
powef f is done by the evaporation Of
volatile liquid under high pressure The machines make
Ten tons of ice day were to be made each day by
Locomotive Works at a cost OF about $4,000. The ma
chine when completed was sent, however to Memphis
made fiat and in order to freeze together the cakes
must be fiat. The speaker had finally perfected an
Of ice would forthwith be a recognized industry.
project for rendering audible melodies by electric
Waling each OF whom put forward theories more
practice The method of the former consisted of simple
electromagnet placed at the bottom OF tin receptacle
whose resonance would strike the varying sounds intel
THE MICROSCOPIC SUBSECTION
In the Microscopic Subsection, Prof. Hlgard Of st
Louis submitted paper bearing "Zymotc Fungus"
describing with wonderfully interesting detail the var-
stages of development of the fungus of yeast stag
nant waters and purescent animal matter-a familiarity
with which by NewYork street officials might work the
highest good in the economy OF street cleaning. The
universal power Of yeast ubquitousy observed In all
fSSn ana @ofe or es Intimately and directly
the grand economy Of nature To IT we owe not only
from vinous, acetic and Tactic fermentation; bread,
I cheese, vinegar, and beer. 49, -
to memOriaze Congress in aid OF the project The Off
President-Dr Young, Cambridge.
VicePresident-GeOrge F. Barker Of Yale College
: secretary-F W Putnam SALEM Mass.
A perfect shower of complimentary resolutions were
then passed. lauding the Troans, the Clubs, and all
others who had shed the light OF their apprecative
enance upon the congregation Of scholars The Commit
tee selected to memOrze Congress consists OF three OF
the most eminent in the Convention Prof Loomis Of
Yale Dr. Henry of Smithsonian Institution Washing
tom and Prots. Higard Of WashiDgtoD and Coffin OF
| Philadelphia.
As the hour for adjournment drew nigh the unfinished
papers ordered to be read simply by title aud be
fore O'Clock the last was ended.
The work Of organization started by the Committee
was perfected by the action Of the Convention First
Dr. Hills resolution for an observatory with corps OF
scientific to be established at some conspicuous ele
yaop Of .hs raefc far6ad Received the approval Of
the Committee and was adopted by the Contention.
Invitations had from various cities rendering the
Convention hospitality and cODveniences for the
years session. the choice however remaining between
San Francisco and Indianapolis, which, because of
feasibility, finally chosen, the time being the third
Wednesday in August 1871. A Committee was formed to
prepare the way for holding the Convention for 1872 in
San Francisco CAL and plenary ntrused them
TO make the best terms possible with ntercOntnenal
railroads This ended the work of the session,
stands adjourned 10 in Indianapolis Indiana Aug