A New System for Preventing Collisions at Sea 



sixth sense, enables it to judge the distance to any object 

 by the lapse of time between the sending out and the receiving 

 of the waves, because it takes some time, some fractional part 

 of a second, for a wave to travel from the bat's wings to 

 the object and return to the bat's face^ 



We know that this is the mechanism that gives to the bat 

 what is practically a sixth sense. We know it must be true 

 because it cannot be otherwise. That the bat possesses this 

 power is completely beyond dispute, and this is the only way 

 that it can be accomplished. But all bats do not possess this 

 organ ; the fruit-eating bats that do not fly about in total 

 darkness have large eyes and never possess this organ, although 

 in some cases, we find the rudimentary remains of the organ 

 which they have inherited from their early ancestors, the same 

 as we have inherited the Darwin tip. 



Anyone who has made a study of heat, light and sound, and 

 is familiar with the experiments of Professor Tyndall, must be 

 struck with the similarity of the laws that govern these three 

 forms of energy. If the atmosphere is very clear, the search- 

 light will reveal objects at a considerable distance. In this case, 

 let us see what takes place. The carbons in the lamp become 

 intensely heated and send off certain very rapid waves in the 

 ether. These travel with a marvellous rapidity, strike the 

 object, become modified to some extent, and a portion of them 

 returns and enables us to distinguish the object. It will, there- 

 fore, be seen that it is the waves that we send out that return 

 to us. If we go into a dark room with a candle, these same 

 ether waves are sent out in all directions ; everything in the 

 room becomes] illuminated, and the waves that return to our 

 eyes enable us to know exactly what the room contains. 



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