capacity in a
given time, we should find that instead of being recorded separately and
distinctly as at _a_, each mark would be pointed at both ends and joined
together as shown at _b_, while only perhaps fifteen could be recorded. If
the capacity be still farther increased as at _c_, only perhaps half the
original number of currents could be recorded in the same time, owing to
the fact that with an increase of resistance, capacity, and inductance of
the line a longer time is required for it to charge up and discharge,
thereby materially lessening the rate at which it will allow separate
signals to pass; the number of signals that can therefore be recorded in a
given time is greatly diminished. If we were to attempt to send the same
number of signals over a line of great capacity, as could be sent, and
recorded separately and distinctly over a line of small capacity--the time
limit being of course the same in both instances--we should find that the
{6} signals would be recorded practically as a continuous line. The two
latter cases _b_, and _c_, Fig. 1, clearly shows the retardation that takes
place at the commencement of a current and the prolongation that takes
place at the finish. If the photo-telegraphic system previously mentioned
could be rendered sensitive enough to work on the Atlantic cables, we
should find that only about 1200 signals a minute could be recorded, and
this would mean that a photograph which could be transmitted over ordinary
land lines in about ten minutes would take at least fifty minutes over the
cable. This would be both costly and impracticable, and time alone will
show whether, for long-distance work, transmission by wireless will be both
cheaper and more rapid than any other method. At present wireless
telegraphy has not superseded the ordinary methods of communicating over
land, but there can be no doubt that wireless telegraphy, if free from
Government restrictions, would in certain circumstances very quickly
supersede land-line telegraphy, while it has proved a formidable commercial
competitor to the cable as a means of connecting this country with America.
Likewise we cannot say that no system of radio-photography will ever come
into general use, but where there is any great distance to be bridged,
especially over water, wireless transmission is really the only practical
solution. From the {7} foregoing remarks, it is evident that a reliable
system of radio-photography would secure a grea