EXPLORINGTHEFLOOR 29 



we owe to the cable-laying engineers. For example, 

 repeated breaks of the cable between Funchal, Madeira, 

 and Lisbon, Portugal, necessitated a closer study of the 

 ocean bottom there. "^ The result was the discovery in 

 1882 and the following years of a number of "banks" — 



Fig. 12. Prince Albert I of Monaco 



steep cones, probably of volcanic origin — which rise 

 from depths of between 6,000 and 12,000 or more feet, 

 with their crests only a few hundred feet below the ocean 

 surface. To the practical requirements of the cable 

 companies we also owe the rapid development of the 

 gear used for accurate depth soundings, a development 

 which led among other things to the substitution of a 



