increase the cost without any
corresponding advantage. Almost any engineer can do almost anything in
the way of engineering if not limited by the cost, but the man who
knows just what materials to use and how to use them so that they will
answer the purpose as to strength and durability can save his own
salary to his employer many times over by simply omitting unnecessary
expense.

* * * * *

HOW MECHANICAL RUBBER GOODS ARE MADE.

While the manufacture of rubber goods is in no sense a secret
industry, the majority of buyers and users of such goods have never
stepped inside of a rubber mill, and many have very crude ideas as to
how the goods are made up. In ordinary garden hose, for instance, the
process is as follows: The inner tubing is made of a strip of rubber
fifty feet in length, which is laid on a long zinc-covered table and
its edges drawn together over a hose pole. The cover, which is of what
is called "friction," that is cloth with rubber forced through its
meshes, comes to the hose maker in strips, cut on the bias, which are
wound around the outside of the tube and adhere tightly to it. The
hose pole is then put in something like a fifty foot lathe, and while
the pole revolves slowly, it is tightly wrapped with strips of cloth,
in order that it may not get out of shape while undergoing the process
of vulcanizing. When a number of these hose poles have been covered in
this way they are laid in a pan set on trucks and are then run into a
long boiler, shut in, and live steam is turned on. When the goods are
cured steam is blown off, the vulcanizer opened and the cloths are
removed. The hose is then slipped off the pole by forcing air from a
compressor between the rubber and the hose pole. This, of course, is
what is known as hose that has a seam in it.

For seamless hose the tube is made in a tubing machine and slipped
upon the hose pole by reversing the process that is used in removing
hose by air compression. In other words, a knot is tied in one end of
the fifty foot tube and the other end is placed against the hose pole
and being carefully inflated with air it is slipped on without the
least trouble. For various kinds of hose the processes vary, and there
are machines for winding with wire and intricate processes for the
heavy grades of suction hose, etc. For steam hose, brewers', and acid
hose, special resisting compounds are used, that as a rule are the
secrets of