VIBRATIONS WITHIN OUR KEN AND BEYOND. 



J. A. LiGHTHIPE. 



Tt IS a scientific fact that on a desert island in mid-ocean, miles and 

 ^ miles away from any human being, the waves breaking on a rock 

 make no sound, also, that a fire on the top of this rock will give no 

 light. This is because sound is simpl}^ a sensation produced on the 

 drum of the ear by vibrations having a cycle of from about 16 to 

 something like 30,000; also, light is a sensation produced on the re- 

 tina of the eye by a vibration something like 45 octaves higher than 

 this. To a deaf man there is no such thing as sound; to a blind man 

 there is no such thing as light. With all vibrations we have a 

 phenomena which we call resonance, that is, a certain similarity in 

 rate. We pick up and respond to a certain rate of vibration. This 

 is very marked in sound where a tuning fork at the end of a room 

 will set another going at the other side, or the resonance of the piano 

 strings responding when we sing a note to the piano. This is also 

 illustrated by the childish play of "hollering down the rain barrel." 



The vibrations which we call heat are about an octave lower than 

 the vibrations which we designate as light waves. These can some- 

 times be lowered or raised, most particularly noticeable in the Wels- 

 bach burner where we raise the frequency of the heat wave an octave 

 and it becomes luminous, or in fluorescence where we lower the violet 

 note in the spectrum and it becomes luminous. Beyond this rate 

 of vibration which we call light we run into the ultra-violet which we 

 sometimes call chemical rays. In taking a long series of vibrations, 

 perhaps of various shapes, it is astonishing how few of these vibra- 

 tions are well known, since we can see for only about an octave and 

 can hear for only about 12 octaves. We can feel the sensation of 

 heat for probably about two octaves. In between these different 

 periodicities we may discover facts in science of which we have little 

 dreamed today. We know that the vibrations of electric waves are 

 away below those of heat. This practice of "tuning in" has led up 

 to some wonderful new inventions, for instance, with a properly ad- 

 justed spark coil and condenser we can set up vibrations in space to 

 almost any periodicity we like. These vibrations do not affect our 

 known senses in the slightest degree, but knowing that they are in the 

 air, we can "tune in" by means of an antenna wire with adjustable 

 condensers until we resonate in synchronism with the vibrations that 

 are thrown out by the spark coil and condenser at some other place. 

 With this apparatus we can readily detect a make and a break in the 

 spark at the other end. This is the modern development of the 

 wireless telegraph. The distance it can travel is absolutely unknown, 

 as it appears to be a question of the power generated at one end. We 

 know that we can send it around the world, and whether we can com- 

 municate with the fixed planets is simply a dream which may, or 

 may not, come true. We have been mystified as to how ants com- 



33 



