The Baltimore County union. [volume] (Towsontown, Md.) 1865-1909, 1886-05-29
SCIENTIFIC MISCELLANY.
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The records of locust plaques in the warm coun-
tries of the Hast, ihsmoerR rs we'll as IN ancient
times almost surpassH belief. Kirby and Spence
mention an army Of iocusts which ravaged the
Mahratta country, extending in a column 500
miles long, and so compact that it obscured the
sun like an eclipse. Near the close of last CEN
fury, so many persisted in the sea on part of the
African coast that bank three or four feet high,
and about fifty miles long, was formed on the
shore by their dead bodies and the stencil of them
was carried $50 miles by the wind. In another
part of Africa, early in the Christian era, one
plague Of locusts is said to have cansed the death
of SOC, 600 persons; and in SCI nearly as bad q
plague occurred in Italy. Again, in 147S, more
than $4,000 persons persisted in the Vanetian ter
ritories from famine caused by locusts.
THE KEEN EYE OF SCIENCE.
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 Observatory this
nebula had never been seen with the best glasses,
although it has since been detected with the great
telescope of the Pulkova Observatory. The En-
peror of Brazil now announces his Discriminate
to cooperate, at the Rio de Janeiro Observatory,
in the general project Of photographing the entire
heavens, already begun at Paris with such unex-
pected success.
DUST EXPLOSIONS. J.
The Investigations of the Prussian Firedamp
Commission have shown that many mine explosions
attributed to redamp outbursts of gas, are real
" due to fine oal-dust, all kinds of dust appear
ing to be capable of exploding violently when
ignited. The experiments relative to this infam-
inability of coai-dust were devised as nearly as
possible in accordance with the conditions pre-
vailing in practice, and more than two hundred
tests were made, explosions occurring in every
case when an electric spark was produced in q
dust cloud.
PLANTS OF THE ZONES.
In recent lecture in London, Mr.. J. G. Baker
estimated the total number of Enthusiastically
tropical plants as from 40, 900 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 nountsin regions
possible furnish 1000 'more-a total of 0D0
species of what gardeners call alpines, that is,
plants specially adapted to a cold, damp climate
with short summer. Mr.. Baker estimated that
$4,000 species of plants are represented in the
the possessions of Great Britain.
THUNDER, LIGHTNING AND RAIN.
Meteorologists have found that there can be
no thunder and lightning without 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 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 re-
Election upon nearer clouds, at much greater
distance.
THICKNESS OF CLOUDS
Capt H. Toynbee, of the London Meteorologi-
cal Society, has arrived at the conclusion that
clouds of less than 1000 feet in thickness sell
dom accompanied by.rain; and if they are it is
very gentle, consisting of minute drops. With a
thickness of between 1000 and 1000 feet the size
of the drops is moderate. With increasing thick
ness 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 produced E
MISCELLANEOUS.
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 null
berry are only very slightly wet.
The time required for the development of small
pox after exposure to it is very difficult to deter
mine, but is usually supposed to be from twelve
to fourteen days. Prof. FL. Eichorst of Zurich,
has, however, at length succeeded in recording
three cases in which the incubation period is
clearly known, and finds it to be few hours more
than nine days in each case.
An English experimenter finds that, contrary
to general opinion, growth of ivy over house
renders the interior entirely free from moisture.
The Malays, who frequently find ancient stone
axes in the soil, call them ''thunderstones," be-
leving that they proceed from thunderbots.
Maj Gen. E. F. Burton has described certain
large, yellow hornets Of India which disposet them
selves in regular circles upon their nest with their
heads to the centre They thus appear like the
spokes of yellow wheel, and a nest of them is
sometimes mista ken for a sunfower. - - = "
DR.. P. Andres finds thatthe danger of a house
being struck by lightning has Increased three to
five fold in Germany within the,last fifty years,
and supposes this to be due to the impurities from
the ever increasing humber of chimmeys.
Birds, according to Mons. Desplats, evolve
three times as much heat as manuals, absorbing
thrice as much oxygen and emitting thrice as much
carbonic acid.
England has new association in the Junior
Engineering and Scientific Society, to which no
person over twenty-six years old is admitted
tafttr. ufse -.--'' r