Figure 1 shows Dr. Haley's diving bell, with the divers at work. D B L K M P represents the body of the bell. D, the glass which serves as a window. B, the cock for letting out the air which has been breathed. LM the seats. C, one of the two air-barrels lowered alternately to supply air. P, H, two of the divers. F, another diver at a distance from the bell, and breathing through a flexible tube K. This diver is supposed to have a head-piece of lead, made to fit quite close about the shoulders; this head-piece was capable of containing as much air as would supply him for a minute or two; when he had occasion for more air he turned a cock at F, by which means a communication was opened with the air in the bell, and thus, he could receive a new supply at pleasure.
DIVING, seventh edition (1830-42)
(B is just to the left of D)