atent (No. 40,407),
granted in 1868, for "boiling waste rags of fibrous material and
rubber in an acid or alkali, for the purpose of destroying the
tenacity of the fibers of the rags, so that the rubber may be
reground." But this process extended only to the weakening of the
fibers, and not their complete destruction. A later patent, in the
same year, provided for exposing the ground rubber waste to the direct
action of flames of gas or inflammable liquids, by which the foreign
matters would be consumed and the rubber rendered plastic and
cohesive, but it is not on record that this process received any
particular application.

The principal activity of invention in the field of reclaiming rubber
dates from 1870, since which year 37 patents have been granted for
processes more or less distinctive from those which had for their
object only the devulcanization of rubber. Prior to that time the use
of rubber reclaimed from fibrous wastes had been confined practically
to one large factory in Boston and one near New York. One concern, for
a while, bought old rubber shoes and sent them to women in the
country, whom they paid so much a pound for the rubber stripped off--a
very expensive process. There were several claimants for priority in
the matter of reclaiming rubber by the processes which finally became
standard, and some conflicting interests were brought together under
the head of the Chemical Rubber Company. This corporation controlled
the leading patents for the "acid" process, licensing various parties
to work under them, and bringing suits against concerns who reclaimed
rubber without their license. In 1895 the United States courts decided
in favor of the defendants, practically rendering the patents invalid,
on the ground that the inventions claimed under them had been
disclosed by the Hall patents of 1858 and the Hayward patent of 1863.

The two patents upon which the suits for infringement rested
principally were No. 249,970, granted to N.C. Mitchell, in 1881, and
No. 300,720, granted to the same, in 1884. About the same time the
Rubber Reclaiming Company, formed in 1890 by the combination of five
leading rubber reclaiming plants, and working under license from the
company above named, was resolved into the original elements. There
were about that time five other rubber reclaiming plants in the United
States, operating either the "acid" or the "mechanical" process,
besides nine general rubber factories producing