Amador ledger., 1908-01-17

Selenium, discovered by Berzelius
in 1878, is non-metallic element
closely related to sulphur and tellur-
ium. In darkness it is practically a
non-conductor of electricity but when
lighted it passes current readily, and
it is this unique variability that gives
TO the substance great possibilities of
future Importance. The curious pro-
perty has been applied experimental
ly in various ways. 1t has given a
means of transmitting speech along a
ray of light, method of guiding and
exploding torpedoes by light, and it
is employed for sending pictures by
wire. it has been used also for
measuring the Roentgen rays applied
in medicine. Selenium, now sell
ing at so cents to 50 per ounce, is
rare substance in little demand, but
in the United States it has been
produced SUPPLEMENTARY from the
anode shines of the electrolytic re-
fining of copper, and it is probable
that a moderate supply can be OBJ
tanned in this way.
Herbarium sheets already collect
ed show 100 species of trees in the
Philippine Islands, and it is expected
that this number will be increased to
1000 or 1890. The tim Der land is
government property, in care of the
Bureau of Forestry. The maps now
in progress are designed in few
years to represent the different types
of vegetation in the islands, the
location and extent of the different
tracts of timber, and the habits of
the nearly 100 principal timber trees.
Electrolysis of pipes is now pre-
vented by insulating from the
ground. The pipes are covered with
specially prepared asbestos paper,
coated with waterproof insulating
compound, and joints are made tight
by strips and insulating cement The
protection is claimed to be perman-
emily durable.
Our eyes need protection from the
invisible rays of our lamps, as shown
by Drs. Schanz and Stockhausen at
the recent congress of German
naturalists and physicists. DR..
Stockhausen was made seriously ill
by the ultra violet rays from electric
arcs, and Investigation has proved
that with increasing intensity and
temperature our artificial iIluminants
have acquired greatly increased
percentage of such rays, although
sunlight itself is not very rich in
them. In the tests made, ordinary
eyeg glasses cut off only the least act
i've portion of these rays. The lens
of the eye protects the retina to a
large degree, hut reasons have been
found for concluding that the lens it.
self is slowly altered, while it is
possible that the cataract of old age
is FASTENED by ultra violet rays, and
the front of the eye is doubtless irri-
tated. An efficient safeguard seems
to be still lacking, although an i'm
proved glass absorbs an increased
amount of ultra violet rays.
Perhaps no industry has shown
greater development in the last year
than the making of chemical appar-
atus from silica. Evaporating basins,
beakers, crucibles, TASKS, retorts,
testtubes and other vessels are now
made wonderfully clear and homo
geneous, and the cost has been reduc-
ed 70 per cent. The advantages of
the new utensils are really eXtraor-
binary. The vessels are thin, strong,
tough and harder than ordinary glass,
they are not cracked by the most vIo-
lent and sudden changes of temper
allure, they will endure about the
same temperature .as platinum with
out melting, and their expansion is
about a seventeenth of that of plat
mum.
The bursting of balloon at Milan
year or moro ago has been traced
by Il. Namias to phosphoric and
arsenic acids present in tho impure
hydrogen used for initiation. spots
on the envelope showed whore these
acids had attacked aud weakened the
fabric, which was strong elsewhere,
This risk in ballooning can be avoid
ed by using pure materials for gener-
ating the gas,
The career of the househy in cities
like Liverpool has been the subject