Los Angeles herald., 1905-11-12
Concrete Used i'm BUILDING

Stacked line and sand. When this
mixture is exposed to the air car
Donate of calcium is formed, the water
is set free and the mass becomes ex-
tremely hard The plaster after it has
set will dissolve in water containing
carbon dioxide, and hence it is not a
very durable material.
Hydraulic cement, namely, a cement
that will set and remain hard under
water, was invented by John Smeaton.
an English civil engineer, who was
chosen to reconstruct the famous
Eddystone lighthouse in 1855, that the
submerged portion of the structure
might be made permanent, Smeaton
evolved the principle that such lime
stone as would yield not less than 10
per cent of residue when dissolved in
hydrochloric acid will become fixed If
immersed in water. Hence he called
all such rocks hydraulic limestones
and the cements made from them hy-
draulic cements.
Natural, or Roman, cement was in
troduced by Joseph Parker and this
was practically the first cement to OBJ
tain anything like the results desired.
His product was made of clay, con-
tanning lime and iron, hardening and
then burning it when mixed with lime
and sand.
After the work of Smeaton had been
concluded two other eminent engineers
Parsley, Of England, and Veat, of
France-set about to ascertain the
most feasible method for producing
the highest grade cement, and it was
largely due to the exhaustive expert
ments of these scientific gentlemen
that the subsequent development came
about of what is now familiarly known
as Portland cement
To show that genius is not always
confined to the brilliantly able, a poor
bricklayer in England, Joseph Aspdin
by name, followed on the heels of the
learned savans above mentioned and
in 1924 he was granted a patent for
cement that possessed admirable quail
tiles and, stepping over the vague and
shadowy line dividing experiment from
utility, he actually produced his mix
ture in quantities sufficient to sell. His
cement was made by mixing kind OF
chalk common to England with clay
obtained from the beds of rivers This
mass was dried then heated to a high
degree and when cool 1t was ground
to an exceedingly fine powder When
mixed with water and it had set 1t
presented a gray color. having very
much the appearance of the well loved
Portland stone of that time, and FROM
ever since been known as Portland CO.
ment.
Strange as ii may seem, natural ce-
ment was received with more favor
than Portland cement and commanded
higher prices than the latter. yet it re-
quired years of hard work before the
makers of the last named commodity
could inspire confidence. in their pro-
duct. The few who did erect plants for
it's manufacture in England and on
the continent were related to the in
ventor, either by blood or ties OF
friendship, but the engineers who
should have used II would not be con-
Vinced of it's superior worth. Some
twenty years after, when great sew
erage system was to be built in Lon
don, the work was intrusted to John
Fraut and his Investigations of the
different cements proved what Aspdin
had always maintained, that is, that
Portland cement was infinitely SUI
perior to all others of hydraulic
nature. Fraut's papers on Portland ce-
ment and cement testing attracted
wide attention, and since then its sur
passing qualities have never been dis
puted.
The fexibility of concrete makes il
an ideal building material, and 1t can
be moulded into any design, every de-
tail of which can be brought out so
sharply as though 1t were made Of
hraGG