The herald., 1895-01-01
OUR AsPHALTUM DEPOSITS.
various Products Used for
Divers Purposes.
An Industry that Will Assume Large
Proportions.
Considerable OF this Material Has Been
Ussd for Street Paving with En-
tire Satisfaction.

The asphaltum OF California is CON.
cretsd petroleum. caused by the oxida.
ton and evaporation OF petroleum oil
when it comes in contact with the
atmosphere. 1t exists in the form Of
riscous tar, graduating to hard. brittle
and shining black mass, breaking with
a conchoidal fracture.
The principal deposits consist OF strata
OF sand, the interzpaces OF which are
filed with bitumen in all states of hard
ness, being hard on the surface and be.
coming softer as it ia removed from
atmospheric influences until it lie en-
tirely excluded from the air. when il
becomes liquid.
These strata are frequently OF large
dimensions. in some cgsea being moro
then 100 feet in thickness, and, from
surface indications and exposure, some
OF these deposits must contain over
30,000.0 QUO tons.
The next important form Of deposit il
bitumnized argyll. This occurs in assures.
existing In shale, which are filled with
bitumen of the consistency Of putty.
Some OF these assures are 10 feet In
width and extend for q long distance.
This form OF asphalt contains from 80 to
20 per cent of bitumen. The Impurities
are finely divided shale disseminated
through the bitumen. These impurities
are probably acquired by the friction Of
the bitumen with the shale during ita
ascent.
Sometimes seams OF absolutely pure
asphaltum are found in the shale. These
seams are generally small, being only
q few inches In thickness. Besides the
above described occurrences OF asphalt
there are numerous overf1ows from tar
springs, which contain impurities of all
descriptions. They have been cooked
by q number of accidental or inten-
tional fires 30 az to be comparatively
worthless. Two principles are con-
tanned in asphalts and are reparable by
known solvents, asphaltene and Pc
trolene. These principles do not exist
in asphalts in defined proportions.
ADAPTED FOR DIFFERENT PURPOSES.
By the existing proportion Of shese-
principles. nearly If not altogether, can
be determined the adaptability of the
asphalt to diffefens constructions and
purposes.
For instance, for street pavsments
Asphalt should contain from rs to 81 per
cent OF pstrolens, which should not
lose over per cent when kept at tenn,
perature OF 250 degrees Fahrenheit for
10 hours.
For the manufacture OF varnish they
should be nearly all ssphaltene. AS
phalt in California contains an excess
OF pstrolene, which can be reduced to
the desired amount by heat. Imported
aephal. usually oontaina an excess of
asphaltens. There il no economical
way of getting rid OF this excess OF az
phaltene; consequently those who use
imported asphalt have tried to supply
the deficiency of petrolsne by diifsrens
tempering materials, such 80 coal ter,
residuum oils and animal fats, none Of
which have proved a subasituts Tor
petrolene, while some of them have been
positive injury. In this respect tbs
California asphafts are far superior to
imported asphalta.
THE PROCESS OF SEPARATION.
When the bitumenized sands described
above contain bitumsn possessing the
right proportions of asphaltum and pc.
trolene they have been used for paving
streets in California, a number of miles
having been laid in the towns and cities
of California which have given perfect
satisfaction when the bituminized sand
has been conscientiously selected.
A process OF separating the bitumen
from the sands is now in practical use in
California. several thousand tons of re-
lined bitumen having been shipped and
successfully used in paving the eastern
cities of the United States. Also large
quantity has been used in the construc-
ton OF reservoirs. The demand for this
material 10 constantly increasing, and
from the present outlook it would
seem that in the future this industry
will assums large proportions and be Of
great benefit to California. 1t is ais
ready recognized as indispensable in the
construction of psvementa in the great
cities of the cast, and cannot fail to be-
come equally 20 in California. Its use
in hydraulic construction of all kinds ID
hardly less important snd is certain &c
reach enormous proportions throughout
the whole Psciic coast, where the sub
ject of irrigation with ito necessary ac-
compartments Of reservoirs. fumes, tun-
nels and aqueducts is daily assuming
greater and creator importance.
A. s. COOPER.