Chapter 3 



PROTO-BATHYSPHERES 



WITH the coming of the Renaissance and the first 

 printed books, actual designs for diving devices 

 suddenly appeared, and with each century, from 

 the sixteenth to the present, their numbers have increased 

 in a sort of geometric progression. 



During the early part of the sixteenth century, in sev- 

 eral editions of Vegetius' De Re Militari, illustrations 

 were inserted of a diver equipped on the same principle 

 as Aristotle's elephant and sponge diver (Figs. 7 and 

 9). A tight-fitting leather helmet with eye openings of 

 some material has a leather pipe leading up to the surface 

 where it is supported by an air bladder. The gentleman in 

 the illustration is apparently not, at the moment, on mili- 

 tary business bent, although he carries a long halberd, and 

 is girt about with a sword, for in his left hand he grasps a 

 good-sized fish. He is shown four feet beneath the surface, 

 which is about the limit of usefulness of this apparatus, 

 for the water pressure on the lungs at any greater depth 

 would make it extremely difficult to draw down an ade- 

 quate supply of fresh air from above. 



The first European diving bell seems to be only an en- 

 larged copy of Aristotle's submerged pot or vase. About 



42 



