ELECTRICAL ENGINEERING PROBLEMS 627 



progress of this beautiful new technical art. But fortunately for 

 the art, it is so attractive that in spite of its associations with many 

 apparently disreputable characters it is still cultivated by serious 

 men of true scientific spirit and devotion. These men know quite 

 well that there is one wireless scheme only, that it is a clean-cut 

 invention of the first order, and being such it is fairly certain that 

 it belongs to one man only, the decrees of the Army and Navy 

 scienticulists notwithstanding; and they also know that it devolves 

 upon them and upon the original inventor, and not upon the scien- 

 ticulists of the Army and Navy, to solve the present problem of 

 wireless telegraphy, which they feel confident to be a true engin- 

 eering problem, because its solution is quite within reach of the 

 present state of the electrical art. This problem is: A rapid, re- 

 liable, and selective communication between the continents and 

 any point on the Atlantic. A ship on the ocean should always be 

 in electrical touch with land. 



That which is needed is an oscillator, sufficiently powerful and 

 persistent to produce strong resonance effects. A wave-train con- 

 sisting of say thirty complete waves is for all practical purposes 

 as effective in producing strong resonance effects as a continuous 

 train. 



In wireless telegraphy oscillators of a frequency of about one 

 million oscillations per second are commonly used. To give a wave 

 train of thirty complete waves the oscillator would have to main- 

 tain its vibrations during an interval of approximately one thirty 

 thousandth of a second. An oscillator of this frequency and possess- 

 ing a condenser of .1 microfarad charged up to 50 thousand volts 

 would during that brief interval of time radiate energy at the rate 

 of approximately 15 thousand horse-power. Assuming that the 

 giant Marconi radiator has an area of 1000 square yards, there would 

 proceed from every square yard during a time-interval of one thirty 

 thousandth of a second radiant energy at the rate of 15 horse- 

 power. The radiant energy sent forth into space by every square 

 yard of the bright surface of the moon, assuming even that it re- 

 flects all the sunlight which falls upon it, is sent out at the rate 

 which is less, considerably, than one horse-power. Yet, although 

 its distance from us is so enormous, our eye can feel its radiant 

 energy even some time before the full moon has risen above the hori- 

 zon and we can measure the relative amount of its radiation, sent to 

 us, by electrical receivers which do not differ essentially from some 

 forms of receivers employed in wireless telegraphy. This simple 

 comparison shows what an intense source of intermittent radia- 

 tion a Marconi radiator can be when actuated by a sufficiently 

 powerful oscillator. A generator of 15 horse-power would be quite 

 sufficient to charge such an oscillator a hundred times per second, 



