146 LIGHT SCIENCE FOR LEISURE HOURS. 



startled by the narrative. The appearance of the 

 ooze-covered cable as it was slowly raised towards the 

 surface, and the strange thrill which ran through those 

 who saw it and remembered through what mysterious 

 depths it had twice passed ; its breaking away almost 

 from the very hands of those who sought to draw it on 

 board ; and the successful renewal of the attempt to 

 recover the cable, all these things were heard of as 

 one listens to a half-incredible tale. Yet when that 

 work was accomplished deep-sea dredging had already 

 been some time a science, and many things had been 

 achieved by its professors which presented, in reality, 

 greater practical difficulties than the recovery of the 

 Atlantic Cable. 



Recently, however, deep-sea researches have been 

 carried on with results which are even more sensational, 

 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 beneath 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 con- 

 trivances men of science have been able to measure the 

 temperature of the sea at depths where the pressure is 

 so enormous as to be equivalent to a weight of more 

 than 430 tons on every square foot of surface. 



The results of these researches are even more re- 

 markable and surprising, however, than the means by 



