A New System for Preventing Collisions at Sea 



and accurate working, but this trouble is overcome by mount- 

 ing them as shown in Plate 5. They are placed inside of a 

 large hoop and suspended by eight pure rubber straps. This 

 effectually prevents them from participating in any of the 

 vibrations that are peculiar to a high-powered ship. 



At a mean temperature of 50 F. sound travels 1,100 feet 

 in a second of time. It takes sound 4.8 seconds to travel 

 one mile and 9.6 seconds to reach an object one mile distant 

 and send back an echo. 



The guns of H.M.S. Thunderer were recently heard at 

 a distance of 100 miles. 



42 



