The Middlebury register. [volume] (Middlebury, Vt.) 1850-1882, 1874-07-14

On THE PERIoDIcITY OF CLIMATES ON
THE EARTn.-The question whether there
are any other regular periods than the
daily and annual in meteorology has as
is well know, attracted great attention
Of late years in connection with the sup.
posed discovery Of an eleven.yea period
coincidng with the increase and diminu.
ton Of the solar spots. Such period
has been argued from observations Of
temperature, terrestrial magnetism, ,auror-
as, atmospheric electricity, and finally,
the recurrence of cyclones in the Indian
Ocean. The most extended labor on this
subject is, however, that of DR., Hopper,
ofthe Physical Observatory of st. Peters.
burgh, who has, with great labor, CON-
bined together an immense mass of obser-
vations Of the temperature in order to
establish his conclusions upon irrefragablo
bases In his opinion, in which doubtless
all coincide, it is absolutely necessary
that observations should be gathered
together from all regions of the world,
and that our conclusions be not based up
on single serious made at any station,o or
over any country. There seem to have
been no observations of temperature made
in any portion Of the world that have not
been used by him, so his conclusion may
be said to embodJ all that can be deduct.
ed from the present state of observational
meteorology. Arranging the stations
according to meteorological zones, the
tropics and sub.tropics, the warmer tenn.
perato zone, the colder temperate zone,
aud the cold zone, he throws the mean
temperate for each year and each zone
into the graphic form of curve, which
can then be directly compared at glance
with the curve OF sun-spots as deduced
bv Wolf from all known observations Of
the sun. At the very first one is struck
with the great agreement of these curves.
La the torrid zone the maximum of heat
occurs from six months to eighteen months
before the spot maximum. 10 the north
of the tropics the maximum of tempera-
ture occurs still later than the maximum
of spots. being retarded even as much as
three years. The regularity and magni.
tude Of the variations of temperature are
beautifully displayed within the tropics,
and diminish as we proceed thence to-
ward the pnles The length of the period
between the maximum temperture varies,
as also does that of the suns spots, so
that, as the Interval between the minim-
um and maximum of spots is almost
always shorter than the interval between
the maximum and minimum, so does the
temperature follow precisely corrcspon.
ding change, The parrelelism in the
series Of numbers is so great that there
no longer remains the slightest chance oi
mere accidental coincidence between
these apparently independent variations
The two phenomena evidently are connec
ted, but in what manner can not at pres.
, eut be determined Only this is clear
that the suns spots do not tdirect through
!, the darkened portion o! the suns disk
act like an eclipse, leaving the remain
ing portion Of the suns disk to shine
upon the earth with undiminished inten
sity, for were this the case, since tht
, temperature o. the earth's surface is
f summation of the total radiation from the
sun, it would follow that the variation in
the temperature would necessarily follow
later than its causc-that is to say, The
, minimum temperturc on the earth should
to q certain extent. follower the max imuu
, number of sun.spots.
+ The contrary, however, is the case the
| number of sun spots attaining its maxi
, mum Of temperature in the tropics, and
it appears to the author most likely thai
the temperature of the suns surface, frou
, some unknown cause, is highest one OF
f two years before the minimum Of the
solar spots, Regarding these spots a,
, comparatively cold matter slowly melting
, away on the glowing surface of the sun
, he remarks that it can not be surprising
that the spots should occupy so great 0
time to completely melt when we con
, slider their immense dimensions. He
, however, finds 10 explanation Of tho re
, markable fact that the retardation of thu
temperature on the carths surface, with
, respect to the suns spots, is greater neal
: the poles than at the tropics, unless i
, have to do with the phenomena of the
: moisture in the atmosphere. To thi
subject, therefore, he proposes to dircc
, attention. In conclusion. as the result
of his studies into the appearance of ex
tremely hot and cold years, he states that
according to the data now before him
there is reason to expect n very cold year
in 1875, iD Europe.-EpIToR's SCIENTIFIC
RECORD, in Harper's Magazine 70,
, .June.