The Baltimore County union. [volume] (Towsontown, Md.) 1865-1909, 1888-02-04
Correspondence Baltimore County Union.
SCIENTIFIC MISCELLANY.
KNOWLEDGE Is HEALTH.


KNOWLEDGE Is HEALTH.
At the recent Hygienic Congress in Vienna,
Herr Won Pettenkofer urged the great Importance
of general teaching in the public schools of
the influence of air, water and soil the public
health. What scientific hygiene has accomplished
was illustrated by the of London, where in the
seventh century, with less than 1000, 900 inhabi
tants, the average death-rate was AZ per 1000 per
year; while now, with population of 100000,
it is less than 81 per 1,OOO That is, science has
more than doubled the average life of the LOndoner.
In the Crimean war, the French lost 95, 900 men,
of whom only 10000 killed. while II, 900 died
from disease. In the Franco German war the eff
fects of hygienic teaching in the military schools
was already apparent, for out of total loss to the
German army of 4O,SSl, there were only 1922
deaths from disease.
GEOGRAPHICAL HARNESS.
A surprising ignorance in geographical matters
prevails even among people Of culture Many ex-
amplss of this have been lately collected by Col.
Sir Charles Warren. In one educated sur
veyor could not free himself of the idea that Paris
was north Of London, and another located the
west end of London toward the eastern coast. Out
of thirty wel-instructed men, from eighteen to
twenty years old, about eighteen were under the
impression IuaG Wule sun rises IN the east the
stars rise in the west.
TREE COVERING MANY ACRES.
The banyan tree is one Of the remarkable pro-
ducts of the East Indies. Its life is usually begun
from q minute seed dropped by some bird upon
some other plant, such the wild date, which it
brushes as it grows. Every branch from the main
body throws out its roots, which, constantly
thickening, descend to the ground several yards
below, where they strike in, increase to large
trunks and send out branches from their tops,
which in turn repeat the process. The Botanic
Garden at Calcutta contains great bauyan now
about century old, which has parent trunk AZ
feet in circumference, 232 root-trunks, ranging
frnpa few inches to foot around, with vast
L1J-erown 857 feet in circumference. Near the
hill fort of Wysatgarh, in the Bombay presidency,
is a banyan whose top in 1882 measured 1887 feet
in circumference. Other specimens greatly exceed
even this prodgious size, single trees being said
to cover Is acres. The famous banyan under
which Alexander the Great stopped on the banks
of the Nerbudda, once sheltered 1000 men, and
when seen by Forbes generation ago, though
much reduced in size by foods, was still nearly
1000 feet in circumference, and had more than g.,
600 trunks.
PRACTICAL HINT.
A German authority recommends as very efec-
tual apparently very simple method of protec-
ting iron from rust. The article is immersed in a
nearly saturated solution of chloride of tin, then
washed in water, and afterward with weak ammo
MIA. The tin solution must not be too acid, or it
will attack the iron. The treated metal appears
like frosted silver.
SOUNDING BY SOUND.
On some parts of the coast of Sumatra and the
neighboring islands, writes Mr.. W. Mattieu Will
liams, the fisherman test the depth of the sea- and
also the nature of the sea bottom, by the noises
they hear on applying the ear to one end Of an oar
of which the other end is plunged in the water.
At depth of twenty feet and less, the sound is a
crepitation similar to that produced when salt is
thrown on burning charcoal at fifty feet it is like
the ticking of watch, the tick-tack being more
or less rapid, according to whether the bottom is
entirely of coral alternately of coral and mud,
of sand. If the bottom is entirely of sand, the
sound is clear; if of mud, it resembles the hum
ming of swarm of bees. On dark nights the
fishermen select their fishery grounds to these in
locations.
FORMATION OF FLOWERS
1t has-been discovered by Prof. Sachs, the dis
tinguished German botanist, that the ultraviolet
and invisible rays of the solar spectrum especially
promote the development of flowers, whose growth
Is exceedingly feeble when those rays sup
~ssed, although that of other parts of the plant
very luxuriant. Prof. Sachs supposes that ex
emely minute qualities of one more substances
e formed in the leaves, and act upon large guam
tiles Ofplastic substances to produce the flowers.
Dividing the solar spectrum into three distinct
gions, or sets of rays he finds that the yellow and
adjacent rays cause the decomposition of carbonc
ACID IN plants, and are active In assimilation; the
blue and visible violet rays are those which pro-
duce the movements of irritation; while the ultra
violet form in the green leaves the substances
which are active in developing the flowers
MISCELLANEOUS.
In the Bodleian Library, at Oxford, faded ink
parchment, ETC., is restored by means of solu-
ton Of hydrosulphide of ammonia.
mushroom plantation has been established in
q disused railway tunnel at Edinburgh. The
mushroom beds occupy about 500 yards of the tun-
nell whose total length is about three-quarters of
SqiIe.
y e. sdIias, a European Psychologist, has shown
Eng is the result of irritation of space
medulls oblongata about one-ffth of an inch
long and one-twelfth wide, and believes that the
brains of ruminants, rodents and other non-Eomit
ing animals, lack this vomiting centre"
prize of $500 has been offered for the produc-
ton Of the best practical elementary textbook of
tropical agriculture specially applicable to Jamai-
ca, manuscripts to be submitted to the Government
of Jamaica on or before Aug. l, 1888. $50