The Mankato free press. [volume] (Mankato, Blue Earth County, Minn.) 1879-1924, 1886-06-18
SCIENTIFIC MISCELLANY.

An English experimenter finds that,
| contrary to general opinion. a growth
of ivy over house renders the interior
entirely free from moisture.
The Malays. who frequently find an
cient stone axes in the soil, call them
Thunderstorm" believing that they
proceed from thunderbOlts.
Birds, according to Mons. Desplats.
evolve three times as much heat as
mammals, absorbing thrice as much
oxygen and emitting thrice as much
carbonic acid.
A line of soundings just completed
across the South Pacific from New Zea-
land to the Straits of Magellan. by Com
mander Barker, u. S. N, found 5000
fathoms, near Chatham Island, the
greatest depth.
A member of the Royal Horticultural
Society of London has observed that
dahlias collect much dew on their
leaves; the peach, rose. and evening
primrose. very little; while the ounce
and mulberry are only very slightly
| wet
Major-General f. +. Burton has dc.
scribed certain large yellow hornets of
India which dispose themselves in regu-
lar circles upon their nest, with their
heads to the center. They thus appear
like the spOkes of a yellow wheel, and q
nest of them is sometimes mistaken for
q sunflower.
Meteorologists have found that there
can be no thunder and lightning with
out rain When thunder is heard
beneath clear sky, the reports must
either come from distant clouds or be
the result of some other cause than a
discharge of electricity. Harvest or
heat lightning is produced by distant
storm. Thunder seldom accompanies
heat lightning, the sound reaching only
about twelve miles. while lightning is
often seen, by reflection upon nearer
clouds, at much greater distance.
Captain ii. Toynbee, of the London
Meteorological Society, has arrived ut
the conclusion that clouds of less than
1900 feet in thickness are seldom ac-
companied by rain, and if they are it is
very gentle. consisting of minute drops.
With thickness of between 1000 and
1900 feet the size of the drops is mod
crate. With increasing thickness comes
increasing size of the drops, and at the
same time their temperature becomes
lower, until, when the thickness is
greater than 5000 feet, hail is pro-
duced
In recent lecture in London, Mr.
j. G.. Baker estimated the total number
of Enthusiastically tropical plants as
from 10000 to $4,000. The plants of
the north temperate zone embrace
about 10000 species. The Arctic zone
has less than 1000 species, while the
higher mountain regions possibly fur
nish 1000 more-a total of 5000 species
of what gardeners call alpines, that is
plants specially adapted to a cold,
damp climate with short summer.
Mr. Baker estimated that 10000 species
of plants are represented in the possess
sions of Great Britain.
A striking illustration of the value of
the camera to astronomy is furnished by
the recent discovery OF new nebula
near the star Maia in the Pleiades.
Until photographed at the Paris obSer-
vatory this nebula had never been seen
with the best glasses, although il has
since been detected with the great tele-
scope of the Pulkova observatory The
emperor of Brazil now announces his
uctcriilnltlon 10 Cooperate 1T lnc MO
de Janeiro observatory, in the general
project of photographing the entire
heavens, already begun at Paris with
such unexpected success.
The investigations of the Prussian
Fire-damp commission have shown that
many mine explosions attributed to fire
damp, or outburst Of gas, are really due
To fine coal dust. all kinds of dust APP
pearing to be capable of exploding
violently when ignited. The expert
ment relative to this inilammability of
coal dust were devised as nearly as pos
sible in accordance with the conditions
prevailing i'm practice, and more than
two hundred tests were made, explosions
occurring in every case where an cleo
trio spark was produced in a dust
cloud.