SOME REMARKS ON THE OPERATION AND 

 USE OF THE APPARATUS 



THE apparatus for producing the atmospheric vibrations should 

 be placed well forward on the main deck or in any other 

 position where it can be turned about from port to starboard. 

 It should be very firmly secured to the deck, and connected 

 with a high-pressure boiler by a three-inch pipe. A straight- 

 way valve should be placed in the pipe near the boiler, and 

 means should be taken to prevent accumulation of water in 

 the pipe leading to the apparatus. 



Of course, there would be no use for the apparatus except 

 in dark, foggy or stormy weather, unless it was to be used 

 for communicating with other ships. When, however, the 

 presence of other ships or icebergs is suspected at night, the 

 apparatus should be used constantly, sending out the blasts 

 in every direction. If the sea were perfectly clear, the blasts 

 sent out would be recorded at the very instant of their pro- 

 duction, but no echo would be returned other than that due 

 to the waves of the sea, which would produce a zigzag line 

 of small amplitude ; but if there should happen to be an object 

 of any considerable size at a distance no greater than two 

 or three miles, the zigzag line on the paper would be changed, 

 the amplitude of the waves would be greater and would be 

 very noticeable. To make sure, the blasts could be repeated 

 several times ; and then, if the result should be always the 

 same, it would indicate the presence of some object, and the 



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