Amador ledger., 1906-11-09

III pFOV6Q Level.
About eighty years ago, DIR. Robert
Brown discovered that microscopic
particles-such as powdered indigo,
earmine, gamboge, etc., keep in
rapid movement when suspended in
water. The peculiar oscillations may
continue for years, and seem to be
the nearest approach to perpetual
motion yet observed. 1t lately oc-
Cured to Drs. Carl Herring and E. f.
Northrup to test the influence of an
electric current upon this Brownian
movement. When the suspendin2
liquid was placed between two eIec-
trodes, the PARTICLES took a very de-
cided course across the field, some
being attracted to one electrode and
some to the other. Each particle
had its characteristic direction, and
in some mixtures the PARTICLES of one
material Travelled with the current
and those of the other against it.
The motion was so positive that DIR.
Northrup has made it the basis of Il
successful electrical measuring in
strument for special purposes.
Everybody knows that plants grow
largest in rich soil, but it is not SO
we'll understood that the largest roots
may be found in very poor soil.
This has been made subject of slate
experiments by a French botan1st
Lots of COLA seeds we're planted
respectively in washed sand, in soil
exhausted by many crops, and in
good soil; and after seven weeks,
with like watering, the roots of the
first lot had grown IA to 16 inches, of
the second lot 10 to II inches, and of
the third lot only 6 inches. In the
poorest soils the roots must extend
farthest to get nutrition.
Delicate speed regulating apparatus
is required when dynamo is geared
direct to a windmill. In a new
system, the windmill pumps water
into a hydraulic accumulation, and
water from this-kept by automatic
valves at pressure of IS pounds per
square inch-drives the dynamo. A
storage battery saves the surplus
power in the usual way.
The novel and ingenious anemo-
meter of K. GoldschmIdt, Belgian
depends upon variation
in electrical resistance due to the
cooling by the wind of an electrically
heated platinum wire. 10 compen-
safe for the changing temperature of
the air itself two similar wires are
used, and these form arms of kind
of Wheatstone bridge, which Is so
adjusted that when the two wires are
Of equal resistance the galvanometer
il at zero. After this adjustment, the
cooling of the exposed wire-the
other being protected-varies with the
wind. The gaIvanometer-w which may
be at considerable distance away-is
correspondingly DETECTED, and gives
a direct reading of the winds veloc-
ity, the indications having been
elaborated by driving one
of the instruments on a rotating
stand through calm air at a series of
known speeds. With a recording
galyanometer and an electrical
weathercock-the later acting through
changes of contact on circular
slide wire-a permanent record can
be kept of both the Velocity and the
direction of the wind.
A little apparatus of great utility
is the fUnilens" telescope lately
produced by London opticians. 1t is
simply convex lens mounted in a
metal ring having a projecting screw
at one side, the lens being ~ inches
in diameter and having a focal length
of feet. The instrument serves as
a very good field-glass. In use, it
length or screwed to the end of a
stick and at maximum efficiency
about 6 feet from the eye-it magni-
fies four diameters. 1t is especially
recommended for observing birds and
plants. 1t is not intended as an
astronomical telescope, but shows 8
stars in the PleIades, where the un-
aided eye usually sees 6.
Working with X-rays is liable to
cause dermatits, and the president of
the British Electro Therapeutic So
ciety, has suffered for two years from
40 or so warts on each hand. The
pain is constant and severe. On the
other hand, Prof. lmbert, of Mont
peIIer, reports that like exposure has
restored the color of his hair and
beard, which had long ago turned
white, his present appearance being
very youthful.
The unfamiliar living world of the
little, with its activities, domestic
relations and tragedies, lis brought
into better view by the bioscope, or
long focus microscope, of M. De-
Gasparis of the University of Naples.
70 be considerably magnifled under
the ordinary microscope, insects
must be brought within a fraction of
an inch of the lens, and with the
frightfuI observing apparatus so near
their movements must be far from
normal. The new instrument is very