28 THE OCEAN FLOOR 



much vaster water masses being "azoic," that is, a region 

 of death. However, in the following decades the 

 dredging of northern waters, especially by British and 

 Scandinavian biologists, proved Forbes wrong. In fact, 

 an abundant life rich in new, unknown species was 

 found to exist at great depths. The death blow to the 

 idea of a zero line at 1,800 feet was dealt by the dis- 

 covery — made in 1862 when a telegraph cable laid 

 along the bed of the Mediterranean was raised for 

 repair — that corals had attached themselves to it at a 

 depth of more than 7,000 feet. 



The laying of submarine cables over great ocean 

 depths, which had been started about the middle of the 

 nineteenth century, afforded a practical purpose for 

 deep-ocean research quite apart from the growing in- 

 terest of scientists in the problems of the ocean floor 

 and its inhabitants. The laying of such cables requires a 

 very careful bathymetric survey along the proposed 

 line of communication, not only with reliable depth 

 soundings but also with samphngs of the kind of sedi- 

 ment on which the cable will be resting. This explains 

 the conspicuously linear arrangement, with closely 

 interspaced depth figures, of the mechanical soundings 

 taken for this purpose. Over the rest of the ocean bottom 

 only a sparse network of soundings was made, as shown 

 by the well-known bathymetric chart of the North 

 Atlantic, the "Monaco chart," inspired by the late 

 Prince of Monaco, Albert L 



Several important discoveries of abyssal morphology 



