The Baltimore County union. [volume] (Towsontown, Md.) 1865-1909, 1907-05-11
Correspondence Baltimore County UssiOn.-
SCIENTIFIC MISCELLANY.


A Novel Sounding Method-Rock as q
Tertilizer-An Optical Magnet-Water
That Stops Ships-Pollen Poison-Ce-
ment Chimneys-New Wave Measure
ments-Food Chemistry-A Wireless
Lookout.
The depth Indicator for torpedo boats designed
by Harold Yarrow. the British shipbuilder de-
ponds upon the fact that vessels bow rises as
shallow water is approached. The apparatus
consists Of base, with fixed level and an adj
justing screw, and two uprights carrying a
series Of six adjustable spirit levels. The levels
are given inclinations corresponding to differ
emit speeds and depths as shown by experiment.
The first level being set for an inclination OF TX
inches IN 20 feet for instance the passage q the
bubble across the level when the boats speed is
10 knots would indicate depth of 90 feet, and
the other levels would respond to shaIlower
water. As the water is usually calm in fog, the
indicator would be available when most needed.
~
The formation Of virgin soil from the rock is
supposed to have taken thousands of years, and
this may be true when the source of the materi-
al has been lodges and buolders. To determine
how quickly pulverized rock can support plant
life is the object of the experiments now in pro-
gress at Washington. If water releases the pot
ash Of ground feIdspar the first season apromis-
ing new fertilizer is available, but If a longer
time is necessary the application of the feldspar
would not be profitable.
~
The plane of poarized light was rotated or
twisted by Faraday by passing through plate
glass In magnetic field. Cotton and Moulton
have now developed permanent transparent
magnet, which consists of mixture Of colloidal
hydroxide Of iron and gelatine solidined under
the influence Of powerful magnet. This opti-
cal magnet gives twist to right or left accord
ing to the direction from which the light enters.
A singular balkiness was shown by the Fran
in August 1893, few weeks before entering the
ice on its long drift across the Arctic Ocean. 1t
was steamfng between two ice fringed islands
OF the Siberian coast and its engines were work.
ing at power that should have given speed of
about knots, but it slowed down to a little
more than one knot. The water was smooth,
the current very slight. hansen recorded this
as an encounter with 'dead-water," mysteri-
Gus condition already known to Norwegian
navigators, and some years later he obtained
from Prof. Bjerknes the suggested explanation
that when layer of fresh water rests on the
top Of salt water. ship will not only produce
the ordinary waves at the boundary between
air and water but will also set up invisible
waves at the boundary between the fresh and
salt water, and the work Of generating these in
visible waves gives great resistance to the ship.
Dr.. Ekman, of Christianiania, has now confirmed
this theory by experiments with small ship
models. He finds that vessels may suddenly
enter or leave the dead-water. that it is more
often noticed by sailing vessels than by steam
ers. and that disturbance like the passage of
another vessel or a sudden change Of speed may
breakup the resistance.
~
Hay fever has been proven to be a form Of
pollen poisoning. and ia plants-including
wheat. rye and other grains-are now known to
have toxic pollen. The TOXINS. which vary
greatly. can be used for producing antitoxins.
Late experience has been that mixture Of
sugar and antitoxin from one of the principal
pollens generally cures hay fever and confers a
certain immunity, 222 cases having been treated
with success in 127, improvement in II, and fail
ure In "a.
Reinforced cement is now the favorite ma
terial with British builders of large chimneys.
One already completed in London is $50 feet
high with base 20 feet square, and projected
one ct Northfeet will be 247 feet high and SK
feet in diameter, with foundation IS feet
square.
The height and length of waves have been
estimated, If NJ Berth, French engineer
. Is correct in his conclusions The observations
are usually made from small vessels, and as
their decks are constantly tilted by the waves,
the results are greatly exaggerated. With care
to avoid this error, the highest wave has meas
ured l8 feet. d. Bertin believes, however, that
in southern seas height 10 feet greater may be
reached, and waves may have the rare maxi
mum Of about 1900 feet, or nearly half mile.
There is q relation between length and period.
the longest waves having period Of % seconds.
A period Of 10seconds is not often observed, and
e - 8 segpuds is most common, corresponding to
length of 100 to 800 feet. Heigth of over IS
eet are rare. The short waves are relatively
higher than the long ones, and wave 100 feet
long Is commonly from to Is feet high.
-
The use of food preservatives is reported by
DIR. A. e. Harris, an English health officer, to be
increasing to an alarming extent. The number
Of substances used is multiplying and now ia
cludes alum, alcohol, ammonium acetate, boric
acid and its compounds, carbon dioxide, copper
salts, creosote, fuorine compounds, formic acid,
AorAuaioSuSuo. nyulOeen P0NOAiuo, OAJsen, PJ-
roligneous acid. saccharin, salicylic acid. salt,
saltpeter, sodium carbonate, sugar, sulphites of
sodium and calcium, and sulphuric acid. These
go into fruits, vegetables fish, meats. milk, but
ter. drinks, sauces, pastry, and almost every
kind Of food,
The wireless safety appliance of German
marine engineer is set to work during fogs and
heavy weather. and acts automatically when
two vessels approach within certain distance.
The action closes the steam-pipe to the screw
Of each vessel. This checks the machinery,
gives time for reversing the engines, and pre-
vents collision.