The Wichita daily eagle. [volume] (Wichita, Kan.) 1890-1906, 1892-06-21

stance is wholly erroneous; certain
amount of asphalt compounded with
rubber assists in calendering and dur
ing Inflammation imparts a certain
toughness to the rubber which is not to
be gained in any other way. The pro-
portion used to-day is but small. For
example, what would be known as a
rich compound is eighteen pounds
coarse Para, eleven pounds litharge,
forty pounds whiting, three pounds
asphalt, one-half pound lampblack,
eleven and one half ounces sulphur.
Exactly what asphalt is very few peo-
pie seem to know, and it is almost in
variably in the popular mind confused
with coal tar. Asphalt as a paving
material has been known since the
Babylonian empire, and to-day paving
blocks are found that preserve their
integrity and have hardly begun to
oxidize in spite of the atmospheric
changes to which they have been ex-
posed. 1t is only within late years that
asphalt has been well known in the
United States. 1t looks very much like
pitch, and when ignited burns with a
bright flame, giving off a dense black
smoke. Alcohol, ether, oil of turpen-
tine, naphtha, and many other reagents
easily Dissolve it Its specific gravity is
2.23.
Until very recently all the real as
phalt used in this country was import
ed There is in the island of Trinidad
a lake nearly two miles in circumfer-
ence which is the source of the most of
it, and it is said that near the shore the
asphalt is very hard, but out in the
center it is soft and viscid. When i'm
ported to the United States it comes
mixed with sand and gravel and a
variety of foreign materials, from
which it is separated by heating over a
slow fire for week or more. During
this heating process the impurities of a
lighter nature rise to the top and are
SKINNED off, while the heavier sub
stances settle to the bottom of the re-
ceptacle- There are very large deposits
Of asphalt in France and Switzerland,
and within the last three years quite ex-
tensive deposits have been discovered in
Utah and California, and small ones in
Kentucky. For paving streets it is pre-
pared by grinding first to a powder and
mixed with crude petroleum and fine
sand. 1t is then moulded into blocks of
suita BILE size, or sometimes it is poured
between blocks of paving stones, when
it becomes hard, and greatly resem bles
the natural rock.
Another use for asphalt is in the man.
ufacture of black varnish, where it is
dissolved in oil of turpentine and lin
seed oil and makes an exceedingly dur
able coating. For insulating electric
wires this sort of coating has been found
of great use, and it is said that one of
the best rubbers for wires to-day manu-
featured is made of a fine compound
containing thirty per cent of India rub
Der, the compound after semi-vulcaniza-
ton being dipped in boiling asphalt,
which toughens it exceedingly. As as
phalt is not affected by acids or gases,
and is an absolutely waterproof COM
pound, and as heat and cold do not af-
feet it, it is a valuable article to use in
connection with India rubber, although
if too large quantities of it are put in it
shortens the gum and may during the
process of INFLAMMATION cause it to bis
ter. A great deal of the gum roofing
sold in the United States which is
thought to be India rubber or gutta
percha is made simply from solution
of asphalt spread upon prepared paper.
India Rubber World.