system. Another is Charles E. Scribner, who, by his invention of
that intricate device, the multiple switchboard, has converted
the telephone exchange into a smoothly working, orderly place.
Scribner's multiple switchboard dates from about 1890. It was Mr.
Scribner also who replaced the individual system of dry cells
with one common battery located at the central exchange, an
improvement which saved the Company 4,000,000 dry cells a year.
Then Barrett discovered a method of twisting fifty pairs of
wires--since grown to 2400 pairs-into a cable, wrapping them in
paper and molding them in lead, and the wires were now taken from
poles and placed in conduits underground.

But perhaps the most romantic figure in telephone history, next
to Bell, is that of a humble Servian immigrant who came to this
country as a boy and obtained his first employment as a rubber in
a Turkish bath. Michael I. Pupin was graduated from Columbia,
studied afterward in Germany, and became absorbed in the new
subject of electromechanics. In particular he became interested
in a telephone problem that had bothered the greatest experts for
years. One thing that had prevented the great extension of the
telephone, especially for long distance work, was the size of the
wire. Long distance lines up to 1900 demanded wire about
one-eighth of an inch thick--as thick as a fairsized lead pencil;
and, for this reason, the New York-Chicago line, built in 1893,
consumed 870,000 pounds of copper wire of this size. Naturally
the enormous expense stood in the way of any extended
development. The same thickness also interfered with cable
extension. Only about a hundred wires could be squeezed into one
cable, against the eighteen hundred now compressed in the same
area. Because of these shortcomings, telephone progress, about