The fundamentals of radio, particularly in regard to reception

As it is the object of this paper to explain in some small degree the fundamental principle of radio, it would perhaps be better, at the commencement, to explain the difference between radio and audio frequency. Under normal conditions the highest audible note has a frequency in the vicinity of 15,000 to 16,000, and any frequency above that is generally considered radio frequency. The wave length is the distance (generally expressed in terms of metres) between any two peaks of the wave. These waves are sent out into the ether in a definite form and retain that form until completely exhausted; they do, however, lose in amplitude, and, therefore, although the wave does not lessen in length between the peaks, the height of the peaks dwindle by degrees until such time as the energy is completely exhausted.