7 Guglielmo Marconi 7between ships and land stations. In 1900 also, Marconi
filed his now-famous patent No. 7777 for Improvements in
Apparatus for Wireless Telegraphy. The patent, based in part
on earlier work in wireless telegraphy by Sir Oliver
Lodge, enabled several stations to operate on different
wavelengths without interference. (In 1943 the U.S.
Supreme Court overturned patent No. 7777, indicating
that Lodge, Nikola Tesla, and John Stone appeared to have
priority in the development of radio-tuning apparatus.)
Major Discoveries and Innovations
Marconi’s great triumph was, however, yet to come. In
spite of the opinion expressed by some distinguished
mathematicians that the curvature of the Earth would
limit practical communication by means of electric waves
to a distance of 100–200 miles (160–320 km), Marconi
succeeded in December 1901 in receiving at St. John’s,
Newfoundland, signals transmitted across the Atlantic
Ocean from Poldhu in Cornwall, Eng. This achievement
created an immense sensation in every part of the civilized
world, and, though much remained to be learned about
the laws of propagation of radio waves around the Earth
and through the atmosphere, it was the starting point of
the vast development of radio communications, broad-
casting, and navigation services that took place in the next
50 years, in much of which Marconi himself continued to
play an important part.
During a voyage on the U.S. liner Philadelphia in 1902,
Marconi received messages from distances of 700 miles
(1,125 km) by day and 2,000 miles (3,200 km) by night. He
thus was the first to discover that, because some radio
waves travel by reflection from the upper regions of the
atmosphere, transmission conditions are sometimes more