Amador ledger., 1907-07-05

and the effect upon certain building
stones is disastrous. The acid washed
down by rains attacks the lime of
marbles, lImestones and caIcareous
sandstones, forming gypsum and
causing the surface to swell and crum-
BILE. A treatment for the decay1ng
stonework is the application of soIu-
ton of baryta, which forms an in
soluble suIphate with the gypsum,
and liberates lime, which the car
bonic acid of the air converts into the
original binding cement of the stone.
Referring to an experience at the
Chapter House at Westminster, Prof.
A. II. Church states that carving so
soft as to be brought away by the
finger was made sound and harder
than the newly quarried stone.
The advantages of the magnetic
electrode lamp over thu carbon arc, as
pointed out by q. E. Little, are long
err life, higher efficiency and a pure
white instead of mixed blue and white
light. The negative electrode, from
which the lamp is inaccurately named,
is really mixture of three metallic
oxides, each serving distinct part in
forming this novel and promising
source of illumination. The titanium
oxide renders the arc luminous, the
oxide of iron gives conduetivity when
cold, and the oxide of chromium pre-
vents too rapid consumption.
The new experimental railway near
Berlin is laid in the form of an oval,
with straight double track 800 feet
long and total length of 5761 feet
Motor-cars using steam. electricity
and benzine will be tried. Tests Will
be made with different materials for
bedding. various rails, sIeepers of
OAK, pine, beech and iron, automatic
block-signals, and, in fact, everything
promising to add efficiency to the
German railways.
The transmission of photographs by
telegraph has reached the stage of
practical results, and actual seeing by
wire is expected to follow soon. Korn
reproduces photographs at distance
through the varying electrical resist
ance of selenium, the changing cur
rent registering the lights and shades
Ut successive points in proper place
on sensitive plate at the receiving
end. lhe telestereograph of Belin, of
Nancy, transmits photographs by a
different and purely mechanical
means, on selenium heing used; while
the telegraphoscope of the same in
ventor is designed to produce an
image of any illuminated object or
scene at any distance. 1t is believed
that the problem of really seeing by
telegraph will be solved by making
the images to appear in more rapid
succession than the retina eau separ-
ate them. At present the sending
apparatus comprises a camera obscura
with lens and mirror to reflect the
optical image upon a row of eighty
tiny selenium cells, and a collector
for successfully inserting these cells
in circuit. The receiving station EN-
braces a highly sensitive galvano-
meter with three local circuits. The
principal circuit contains the equili-
orator and a telegraph relay, the
primary circuit of small induction
coil has in turn the second part of
the equilibrator, and the secondary
circuit of the coil has a gap whose
spark, controlled by the distributing
collector, perforates a paper with
very fine holes equally spaced between
centers, but of size varying to CORES
pond with points on the image, This
gives a picture resem bling autotypy.
The equllibrator, the chief part, pro-
vides a local current of sufficient
intensity to register decidedly every
change in the feeble current from the
selenium cells.
To give the greatest possible pre-
clsion to our knowledge of the atomic
weights of the elements, an inter-
national commission corrects the list
each year in accordance with the most
recent discoveries. OF the 70 ele
ments in the latest list. hydrogen is
still the Iightest, with an atomic
weight of LOS. The atomic weight of
oxygen is l6; gold, 1872; radium,
225; and uranium, the heaviest sub
stance, 23S.5; while mercury, thall-
ium, lead, bismuth and thorium are
all heavier than gold.
The compressed air spray has been
used on surfaces, like the Eittel tower,
and for whitewashing tunnels. The
newer art of decorating small surfaces
by means of an air brush seems to
have reached its highest development
In Germany. Of the two types of
apparatus, one is held like a pencil