THE IMPENETRABLE SEA 



expelled it — the upper end of the tube floating on the 

 surface. Aristotle's words have often been quoted, and 

 no doubt contain the earliest detailed descriptions of 

 breathing mechanisms. But there were earlier pictorial 

 representations. The London British Museum contains 

 what may well be the earliest : two Assyrian bas-reliefs, 

 dated about 900 B.C., which came from the palace of 

 King Assur-Nasir-Pal at Nineveh. These show a number 

 of men wearing inflated goatskins at their girdles. Each 

 diver has a short tube in his mouth, connecting with a 

 goatskin, through which he breathes air. Although some 

 archaeologists have suggested that the appliance depicted 

 was used to support soldiers swimming across rivers, the 

 explanation does not account for the tubes, which would 

 have had no purpose if the bags were merely early 

 ''water-wings" ; in fact if the breathing apparatus idea is 

 dismissed one might as well believe that the soldiers are 

 playing bagpipes. 



Roger Bacon is credited with the invention of an 

 underwater breathing device in 1240. 



Giovanni Alfonso Borelli (1608-79) ^^^ the first to 

 introduce an eflScient means of forcing air down to the 

 diver. Modern authors have various misdescriptions of 

 his apparatus. One says the gear was never tested and 

 that the helmet was of brass or tin. But descriptions of 

 Borelli's diving-suit, much nearer to his own time — some 

 of them exhibiting considerable detail — show that it was 

 far superior to the diving bells then being developed. 

 One account says that it was devised for diving under the 

 water to ''great depths" — but the phrase did not in 

 those days imply what it does today. The vesica or 

 bladder (actually the headpiece) was of brass or copper — 

 certainly not tin — and was about two feet in diameter. 

 It was fixed to a goatskin suit, "exactly fitting the body 

 of the person". Within the headpiece were pipes by 

 which a circulation of air was contrived. 



The diver was connected with a bellows on the surface, 



172 



