The Evening standard. [volume] (Ogden City, Utah) 1910-1913, 1910-10-03

forced concrete have different rates
OF eXpension
Bars OF Iron are placed so as to Join
the two walls where The building i9
most pronounced These bars tcrmi-
nate in screws furnished with nuts.
The whole of their length Is heated
and the nuts tightened. In cooling
tho bars will contract, with practically
irresistible force. causing the walls
TO stralghten up. This operation is re-
peated until the process Is complete.
Whether 1t be electricity, magnet
ism. steam, wood coal oil or gas, that
is the direct agent, in the production
OF power-It Is the sun after all that
Is the source OF all energy In the
world. For millions of years the sun
has been bathing the earth with her
radiant energy md storing up for us
in mighty caverns enormous supplies
of energy in the form or coal, oil. gas
and limestone.
To look at a bit OF coal grimy and
strong in appearance one would hard
ly suspect that 1t is practically pre-
served sunlight and heat. First OF all,
we must bear in mind that even as
matter is indestructible. so is that
strange and mysterious something
known as energy. Even as there IS
just as much matter In the universe
today as there was in the beginning.
There Is just as much energy.
No energy is ever lost except In
practical sense The stones that were
carried to the very pinnacle of the
great pyramids remain to this day
Let us recall right here just what
heat unit is. A British Thermole
unit, abbreviated 3. t. u, is an amount
Of heat required to raise pound OF
water through one fathom heat de-
gree. The heat transforms the mate
rial Portland cement is made from
artificial mixtures Of materials con-
taIning lime silica and alumlna in
proper proportions. it is now conceded
by nearly every expert that calcined
Stag cemcnts may be classed as Port
land cement.
Engineers Reviews snys. Port
land cements arc products obtained
from the heating or calcining up to
incipient fusion of intimate mixtures,
either natural or artificial. Of argillac-
ceus with calcareouS substances the
calcined product to contain at least
| ( times as much lime by weight as
of the materials which give the lime
its hydraulic properties to be finely
pulveri2ed after said calcination.'
Portland cementS are tested In tho
following ways;
1-Speci0c gravity. In detecting
adulteration, the following valuable In
dications may be afforded
Fineness-The Sieve5 should be
left thoroughly dry.
Time OF setting-Great care should
be exercised TO maintain test pieces
under as uniform conditions as possl-
BILE a sudden change or vide range
of temperature In the room vitally
affects the rate of setting.
Tensile strength-Each consumer
must fix the minimum requirements
for tensll strength 10 suit his own con-
ditlon.
Constancy Of volume.
Chemical analysis.
Comparative table
| shall not dwell any longer on ce-
ment. 1t Is a very long subject, but
| may mention natural cement
1t Is natural rock calcined at a
heat below incipient fusion and grind
ing the product to powder.
Many people believe the natural ce-
ment TO come from Arkansas and Aala-
bama. where exists small deposits OF
natural cement. Large deposits ex-
ist in Argentina, Brazil and Bolivia
and are used for native construction.
Cement is one Of the most useful,
convenient and economical materials
used by engineers. Next article Will
discuss same.
tSigned) FRANK HOLLAND.