334 



THE POPULAR SCIENCE MONTHLY. 



HOW THE SEA IS SOUNDED. 



BY G. W. LITTLEHALES. 



IT was not until long after astronomers had begun to sound out 

 the realms of space and to measure the distances and weigh 

 the masses of the planets that the longing which has always ex- 

 isted in the human mind to know more of the mysteries of the 

 sea began to be gratified. Indeed, the deep sea remained unfath- 

 omed and mysterious until after the second half of the present 

 century had dawned upon the world ; and the contemplative mari- 

 ner of fifty years ago, as he looked upon the heaving bosom of 

 the ocean and wondered at its mysteries, had -nothing but myths 

 and legends to sustain his meditation. 



Under the stimulus created by the achievements in investigat- 

 ing the earth, the air, and the heavens attempts had already been 



made to fathom the ocean 

 both by sound and pressure, 

 but in what sailors call " blue 

 water " every trial was a fail- 

 ure repeated. 



In 1856, Maury writes: 

 "The most ingenious and 

 beautiful contrivances for 

 deep-sea sounding were re- 

 sorted to. By exploding 

 heavy charges of powder in 

 the deep sea, when the winds 

 were hushed and all was still, 

 the echo or reverberation 

 from the bottom might, it 

 was held, be heard and the 

 depth determined from the 

 rate at which sound travels 

 through water. But though 

 the explosions took place 

 many feet below the surface, 



echo was silent and the sea gave out no answer. Ericsson and 

 others constructed deep-sea leads having a column of air in them 

 which, by compression, would show the pressure of the water to 

 which they might be subjected, and therefore the depth. This 

 plan was found to answer well for ordinary purposes, but in the 

 depths of " blue water/' where the pressure is equal to several 

 hundred atmospheres, the trial was more than these instruments 

 could stand/' 



Lieutenant Maury planned and constructed an ingenious deep- 



Section, Sute Elevation. 



FIG. 1. MODERN SOUNDING CYLINDER. 



