162 LIGHT SCIENCE FOR LEISURE HOURS. 



Recently, however, deep-sea researches have been 

 carried on with results which are even more sensa- 

 tional, so to speak, than the grappling feat which so 

 surprised us. Seas so deep that many of the loftiest 

 summits of the Alps might be completely buried be- 

 neath them have been explored. Dredges weighing 

 with their load of mud nearly half a ton have been 

 hauled up without a hitch from depths of some 14,000 

 feet. But not merely has comparatively rough work 

 of this sort been achieved, but by^a variety of ingenious 

 contrivances men of science have been able to measure 

 the temperature of the sea at depths where the press- 

 ure is so enormous as to be equivalent to a weight of 

 more than 430 tons on every square foot ot surface. 



The results of these researches are even more re- 

 markable and surprising, however, than the means by 

 which they have been obtained. S-ir Charles Lyell 

 has fairly spoken of them as so astonishing " that they 

 have to the geologist almost a revolutionary character." 

 Let us consider a few of them. 



]STo light can be supposed to penetrate to the enor- 

 mous depths just spoken of. Therefore, how certainly 

 we might conclude that there can be no life there ! If, 

 instead of dealing with the habitability of planets, 

 Whewell, in his " Plurality of Worlds," had been 

 considering the question whether at depths of two or 

 three miles living creatures could subsist, how con- 

 vincingly would he have proved the absurdity of such 



