The Baltimore County union. [volume] (Towsontown, Md.) 1865-1909, 1909-08-21

Poisoning Weeds A1one-Darkneee for
Books-A Novel Type Of Architecture
The Twentieth Century Museum
The Magnet as Air Filter-Latest In
e-Saving-Magnetism as Machine
Gearing Blowers-Electrihed
Leaves.
The destruction Of weeds by spraying was be-
gun in North Dakota in 1895 by Prof. H. L.
Bolley, who is widely known also for his re-
searches in plant diseases. He sprayed growing
wheat with solutions of copper sulphate and
mercuric bicloride. and found that the tops of
both grain and weeds turned black. but the
former revived in two or three days. while
young mustard and other weeds withered and
died. The difference in effect is attributed to
the fact that the broad. rough and soft leaves Of
the weeds retain much Of the chemicals. which
run of harmIessly from the smooth and slender
stalks of grain. For sulphate Of copper has been
substituted the cheaper sulphate Of iron. OF
which many tons are now used. killing most
weeds without injury to grain. including false
fax, shepherds-purse. peppergrass, corn cookie.
chickweed. dendelion, Canada thistle. birdweed,
plantain, pigweed, ragweed and others. A solu-
ton of two pounds of sulphate of iron in gal
lon Of water has been found effective in SINH
lar way for freeing lawns from young dande-
lions.
Buildings without windows have received ia
vorable consideration for the book-stacks of
libraries. Daylight is injurious to books. and be-
sides this the windowless structure offers such
advantages as reduced cost, better protection
against fire, exclusion of dust, greater conve-
nience in changing the arrangement Of the
books, and more equable temperature. AS IL
brary stacks are mostly hidden behind other
- ala
walls is not a serious objection. Forced ventila-
ton would give pure air, and artificial air could
be turned on at will.
Considering that circular structures best re-
sist earthquake shocks, Prof. Giuseppe Torres.
Of Venice, has designed house for earthquake
regions consisting of several circular turrets Of
different diameter communicating with each
other. This seems more artistic than econom-
ical.
In the unique and advanced museum idea of
DIR. Goldschmidt. of Brussels, the aim is to go
beyond inert models and bring the public into
contact with science In action, inviting visitors
to test and use apparatus instead of labelling It
Don't handle" His first efforts have been APP
piled to popular electrical laboratory. This Is
divided into graded sections so that the visitor
may first experiment with sealing wax or mag
nets, then with electric generators and motors,
passing further along to tubes in which he may
show cathode rays and other electrical dis
charges and the effects of radium, and reaching
finally the instruments for precise measure
ments, in q section where competent assistants
perform the tests. although sufficiently trained
visitors are permitted to use the instruments.
Some of the more delicate apparatus is kept I'M
der glass. leaving exposed only such parts as
must be handled in making the experiments.
There is q mechanical workshop where any per
son may gain experience in constructing electro
cal apparatus four small laboratories for per-
sonal research by specialists, hall for the free
exhibition of industrial products. lecture hall
where pressing a button causes 100 successive
views to be thrown on q screen, and library OF
the principal scientific books and periodicals.
-
In factories where needles are made. the
grindstones throw OF great quantities Of minute
steel particles, with which the air becomes
heavily charged, although the dust is too fine to
be perceptible to the eye. Breathing the dust
shows no immediate effect, but gradually sets
up irritation, usually ending in pulmonary con-
sumption, and formerly workmen almost all
died before the age of forty. Ineffective at
tempts were made to screen the air by gauze or
linen guards for nose and mouth. At last the
use of the magnet was suggested, and now
masks of magnetized steel wire are worn by
workmen, and effectually remove the metal
dust before the air Is breathed.
s.s
The novel lifebelt of P. Guterman. an English
inventor, is metal strap, adjustable to man or
child, with four air-filled metallic floats about
the size of an ordinary cocoanut. 1t is claimed
that the wearer of the belt must always assume
and keep perpendicular position in the water.
S.
In the novel gearing of Jules Lecoche, lately
brought to the notice Of British engineers, the
two wheels, with spiral or helical teeth. do not
run in contact, but one wheel is rotated by the
other through the pull of magnetism. The tops
of the teeth of the two wheels are separated
about 1-32 of an inch. One wheel is provided
with field magnets that generate magnetic
aux between its teeth and the corresponding
teeth of the opposite wheel, and as the first
wheel turns its teeth pull those of the other
wheel around. The magnetic force is being con-
stantly shifted from one tooth to the next be-
hind it. so that the rotation of the other wheel
is made continuous. There is no friction. and
only three per cent. of the transmitted power is
used in the field magnets, the gearing efficiency
being about 81 per cent. Not least among the
advantages of the new apparatus is the high
speed possible in transmission.
~
Blowing wells, sucking in and expelling air
are known in different parts of the world, and
one explanation is that they are connected
with changes of barometric pressure. Late at
tention has been drawn to three interesting
near Norwich. England. They are 8 feet in d.
ameter, about 70 feet deep and 100 feet apart and
the sucking and blowing often last several days
each. An iron dome over the opening is some
times blown of, leaves being drawn in when
the air current is reversed. The wells are two
miles from the river yare, and 140 feet above
sea-level, the river being four feet higher than
the ocean.
A singular electric plant is said to grow in the
forests of India. Plucking its leaves gives q
shock, and it affects magnetic needle 20 feet
away. The energy is greatest at about O'Clock
in the afternoon. nearly disappearing at night.
The intensity often increases greatly in storms.
but in heavy rains it becomes SO inert as to have
no influence on the compass. No magnetic met
ais are found near. Birds and insects seem to
have an instructive dread of the plant, and are
never known to alight on it.