THE FISHMEN 



included. For convenience we term all these ''fishmen". 

 Those in the other classification, who occupy vessels 

 within which they have freedom of movement — such as 

 diving bells and bathyscaphes — will be considered in a 

 later chapter, for these divers go down to far greater 

 depths. The fishmen — both skin-divers and those who use 

 diving-suits — are compelled to operate in shallower 

 waters, for their bodies could not withstand the tre- 

 mendous pressures of the greater depths. 



Man must have air to breathe, but if that was his sole 

 requirement in going down into the sea, and his body 

 could stand the increasing pressures, it might be possible 

 to send divers down (with tubes connecting them to the 

 surface) to far greater depths than those which are now 

 traversed by men in diving-suits. But the crushing pres- 

 sure of the waters — increasing by nearly half a pound 

 (actually 0.445 pounds) per square inch for every foot of 

 depth — operates like a stern command : "Thus far shalt 

 thou go and no farther." The deeper chasms of the 

 oceans go down for miles, but the diver who is not pro- 

 tected from pressure by a shell of some kind — of steel 

 several inches thick if he wants to descend thousands of 

 feet — must confine his activities to the shore-waters of 

 the continental shelves. 



Perhaps the earliest reliable reference to unassisted or 

 natural diving occurs in the Iliad, where Patroclus com- 

 pares the fall of Hector's charioteer with the action of a 

 diver diving for oysters. 



Thucydides was the first to mention the employment 

 of divers for mechanical work under water. He describes 

 how divers were employed during the siege of Syracuse 

 to saw through the barriers which had been constructed 

 under the surface to obstruct and damage any Grecian 

 vessels which might attempt to enter the harbour. There 

 can be no doubt that divers, even in those early times, 

 had so trained themselves that their lungs could resist 

 the increasing pressures — doubled at thirty-three feet 



167 



