Amador ledger., 1910-09-23

MISCELLANY
Reported weekly sOr the Ledge

activity Is Measured-An Alloy for
Cutlery Plastic Material
Nickel Lithographic ''Stones -
Plants as Living Pumps--A Vacuum
Furnace-An Electric Eraser-Milk
Celluloid
The liability of certain iron-alumi-
mum alloys to fall to pieces spontan-
eously was made known nearly twenty
years ago by Roberts Austen, and
since then the same effect has been
noticed with cobalt, Nickel anthony,
molybdenum manganese and even with
zinc. 1t cannot be attributed to oxida
ton nor to silica. In late paper to
the London Faraday Society, it was
stated that the disintergation follows
the alloys marked expansion, which
on slowly cooling in crucible may
continue for days and even months.
Chilling seems to arrest disintegra-
tion, as samples of the same alloy
that had been cast in im n molds were
perfectly sound years afterwards.
Many aluminium alloys have shown the
property, and reasons have been found
for believing that aluminium exists in
two allotropic conditions. Very pure
aluminium has shown want of con-
hesion when near the melting point.
making it appear that one form must
be very weak and quite useless. An
interesting problem remains for the
metallurgists and they are expected
to show how the alloys can be made
safe
Ra6ioactivity, which has appeared
in so many substances, is measured by
comparing the time taken by the en-
anation in discharging a charged
electr0meter with the time of dis
charge by a standard radioactive sub
stance. Black oxide of uranium is
the standard material. This is so
spread on disk of so square cent?
meters that the radiation per square
centimeter corresponds to that of
centigram of oxide, and on another
disk so centigrams of the substance
under test are spread. Then the time
of the normal discharge of the electro
meter is noted, then the time with
each disk in turn under the needle
the results giving the radioactive
value by formula.
The cobalt chromium alloy of Ed
wood Haynes, Indiana metallurgist, is
claimed to rival the finest steel in
hardness and durability. and it's resis
lance to corrosion specially fits it for
cutlery, surgical instruments, and
various tools.
The new rubber substitute of DR.. F.
G. Weichmann, called 'protal," is
by adding an animal albumen,
with suitable solvent to vegetable
albumen base, which is supplied in a
specially adapted form by the seeds of
certain palms. Protal is perfectly
plastic at first, soon acquiring the
hardness of stone. When first pro
duced, 1T can be pressed into molds or
otherwise shaped while cold, and when
made into dry powder it can be
pressed or nodded on heating. 1t can
be loaded with any of the materials
commonly used with rubber. DR..
Wechmann has used it with more than
eighty different substances, including
asbestos, shellac, linseed oil, cork
-four, pigments, rubber and bakelite,
and has produced compounds having a
wide range of properties, and claimed
to be adapted to the many purposes
for which rubber is employed. An adj
vantage claimed for these compounds
over those of rubber is that they are
not liable to deterioration from oxida-
ton. The great variety of objects for
which these products are recommended
include buttons, chessmen, door-knobs,
picture fra mes, monograph records,
spools, telehone receivers, battery
jars, gun-stocks, trays, tiles, grinding
wheels, electric insulators, automobile
tires, door. mats, soles, weather strips
etc.
The fine grained slaty limestone
used in photographic printing is expen-
sive and cumbrous, and attempts have
been made to use aluminium and other
materials in its place. The latest sub
stitutc is a plate of nickel. A sheet
of brass or other metal is secured so
as to take ink and is then coated with
graphite and made to serve as the base
of deposit of nickel by the electricity