New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1876-02-19
APPLIED SCIENCE.

APPLIED SCIENCE.
CApNrERIrr AyD oUMErTE.-GGrnicrife and
NovpeTie are two new nickel minerals found near
the town Of Nounea in New-Caledonla, and de-
scribed by Prof Ilycrsidgc of Sydney. They are
very similar to each other in appearance. though
they are considered to have some Distinguishing
characters They are amorphous, of a bright
appe-green color and So sof, 10 be easily polished
by rubbing with the thnmh-nail. The economic inn
porancc of these minerals lies in the fact that they
contain about - per cent OF nlckeloAlde, winch as
they occur in large quantities. makes them valuable
~ nickel ores. They both occur hlling veins ana
assures IN scIpentihe
Volcano HISTORY OF IEELiND.-In the annual
address delivered before the Royal Geological Society
of Dublin Prof. Hull has given an interesting ac-
count of the volcanic history Of Ireland. He shows
that in the Lower Siluran there are numerous
examples of volcanic rocks in several parts OF the
island; thus in the counties of wicklow and Water
ford there are numerous sheets OF felstOnes ana
porphyric, accompanied by beds of ash and vol, anc
brecco. and SIMILAR conditions in other districts.
All of these volcanic rocks are TO be regarded
having been crupted from vents sporadicay break
ing ont over the .ea-bcd OF the period. they having
been in turn covered up by fresh sediments. In the
Upper Siluran there is little evidence of volcanic
action; in the Deyonian there more, and in the
Corbomfrror, they are still more decided. Coming
down I'm ia" geological history. 1t - necessary Ia
pas, to the Tertiary before the products OF the
'. lranc fires are AGAIN met with. In Tins period
the, were very active, and tho area now occupied
hy the volcanic rocks ~ tine Northeastern part ol
Ireland may he estimated m - 300 square miles.
tending moreover 10 the west coast ol Scotland
These Last volcanic rruptiuI> are some oI the most
cxtcn-iy, THAI the world has ever known, and 1t Is
10 th,n that To be- referred the strange beauties
of the Giants Causeway and Flnglls Cave.
Tur TrupFRATURE or TIE AR.-One of the most
difficult problems in all matters relating To the atmos-
pherc consists in the determination of the true tenn
peratnre the air; and the errors in these determ-
nations affect very scnSihly both ASTRONOMICAL and
meteorological hyp,ounctric Ehors. Prof. Planta-
mour was among the fits, 10 show that observations
Of the barometer taken simultaneously at two dis
tinct stations ought 10 enable by calculation tn
arrive at the average temperature of the intervening
atmosphere Among those who have lately applied
thi, method is Mr. Schott of the Coast Survey, whohas
from observations made about 30 miles northwest
of san Francisco calculated the temperature of the
air between two stations occupied by Mr.. Davidson.
As the results of these studies il appears that the
average temperature of the air between two stations
differing 1000 feet in altitude remained senSby
constant throLgho the entire day, rs though the
SUMS rays passed through il without apprcciaby
heating #, while, the other hand. the Their
monietrr at the TWO stations respectively rose 10
maximum at | y. m. and lei To- Il Ili,l-
imnm IN the morning and evening. Inc dal,iy
variations of temperature seem, Therefore, 10 DE
confined mainly to the layer of air IN close proximity
to he carhS surface. The corrections Ia he applied
to the observed thermometers. III order 10 Obtain the
true temperature ot the AR, varied regularly
throughout the day, and are decidedly larger than
tho>, obtained by Prof. Plantamour at Geneva. Mr..
Srhott i'm cNpanation of this phenomenon suggests
that probably the 20 or 30 per cent of total solar
radiafion which il absorbed by the atmosphere, Is
consumed IN the processes OF expansion ana eNap0-
ration and tins gives no sensible heat.
NEW Form OF MrRCURIN HoRIZoN.--Those who
have had frequent occasion Ia observe the heavenly
bodies as reflected from bath OF mercury will vel
come the announcement that it is possible 10 con-
sruct such bath i'll Il manner To diminish, if not
entirely obyiate, the very annoying vibrations TO
which the mercury is subject even when the origin
of the vibration is unknown. Such IA bath of mer-
curry established upon a pier of its own entirely
isolated from the building. has been known TO
tremble under the influence of vibrations commun-
Gated from railroad trains or the blasting of rocks,
from two To five miles distant. In the ncighborhood
of large city the surface is never quiet by day or
night In order to ob late this annoyance, il is we'll
known that Prof. Airy of Greenwich suspended the
basin containing the mercury from the fourth of II
set of four frames, each of which suspended
from the other b. threads of nda-nbber. By this
means tue mercury WAS lfltNtu lloHl iut
of the minute vibrations to which the ground near
London is continually subject. Mr.. Lane of the
Coast Survey, however, announces that if in the
bottom of the basin, near its edge, we
! cut circular trough, such that the
greater mass of the mercury may run into il, We
may leave over the greater portion of the remaining
bottom surface of the basin thin layer of mercury,
possibly the one-hundredth of an inch deep which
will not be troubled by the ripples that originate
near the edges of the BASIN Ii is easy he says, by
/ la hp
| starting from the edge, but quickly dying out rs
! they come upon the plateau where the mercury Is
! relatively shoa IL might be anticipated that n
| slight inclination of the basin would ma
tcrially alter the horizonaty of the surface of the
mercury. lie states, however that this is not the
case to any injurious extent, the moncntary fitting
of the mereuria surface being immediately followed
by "A resumption of its horizontality. Mr.. Lanes ar
rangcment Tor procuring thin, steady horizontal
mcIcural film seems to be an Improvement upon that
proposed many years ago by Lamont, and will
doubtless he found exceedingly convenient in many
astronomical observations If 1t he not injurousy
affected by inequalities of temperature, rs Lamont
| showed was the case in his own apparatus.