306 THE PHYSICAL GEOGRAPHY OF THE SEA. 



countless numbers of the lower animals, even where every trace 

 of vegetation has long vanished in the eternally frozen ice, and 

 the cooled sea fosters no sea- weed — that this law, I say, holds good 

 also for the sea, in the direction of its depth ; for when we de- 

 scend, vegetable life vanishes much sooner than the animal, and, 

 even from the depths to which no ray of light is capable of pene- 

 trating, the sounding-lead brings up news at least of living infu- 

 soria." — Schleiden's Lectures, p. 403-406. 



561. Until the commencement of the plan of deep-sea sound- 

 ignorance concerning ine^s, as thcv havc been conducted in the American 



the depth of "blue , , pi , ., -n ,,i i 



water." ^avy, the bottom oi what the sailors call " blue wa- 



ter" was as unknown to us as is the interior of any of the planets 

 of our system. Koss and Dupetit Thouars, with other officers of 

 the English, French, and Dutch navies, had attempted to fathom 

 the deep sea, some with silk threads, some with spun-yarn (coarse 

 hemp threads twisted together), and some with the common lead 

 and line of navigation. All of these attempts were made upon 

 the supposition that when the lead reached the bottom, either a 

 shock would be felt, or the line, becoming slack, would cease to 

 run out. 



562. The series of systematic experiments recently made upon 

 Early attempts at this subjcct shows that thcrc is uo rcliancc to be 

 -unwOTthyT/reu- placcd ou such a supposition, for the shock caused by 

 *°^®" striking bottom can not be communicated through 

 very great depths. Furthermore, the lights of experience show 

 that, as a general rule, the under currents of the deep sea have 

 force enough to take the line out long after the plummet has 

 ceased to do so. Consequently, there is but little reliance to be 

 placed upon deep-sea soundings of former methods, when the 

 depths reported exceeded eight or ten thousand feet. 



563. Attempts to fathom the ocean, both by sound and press- 



various methods tried ^^^j ^^^ bccu madc, but out in " blue water" ev- 

 or proposed. ^^^ ^^.'^^ ^^^ ^^l^ ^ failure repeated. The most 



ingenious and beautiful contrivances for deep-sea soundings were 

 resorted to. By exploding petards, or ringing bells in the deep 

 sea, when the winds were hushed and all was still, the echo or re- 

 verberation 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 concussion took place many feet below 



