DIVING BELL, 



American Society, vol. iv. The exter- 

 nal shape of his vessel bore some resem- 

 blance to two upper tortoise shells of 

 equal size,' joined together; the place of 

 entrance into the vessel being represent- 

 ed by the opening made by the swell of 

 the shells at the head of the animal. 

 The inside was capable of containing the 

 operator, and air sufficient to support 

 him thirty minutes without receiving 

 fresh air. At the bottom, opposite the 

 entrance, was affixed a quantity of lead 

 for ballast. At one edge, which was di- 

 rectly before the operator, who sat up- 

 right, was an oar for rowing forwards 

 and backwards. At the other edge was 

 a rudder for steering. An aperture at the 

 bottom, with its valve, was designed to 

 admit water for the purpose of descend- 

 ing ; and two brass forcing-pumps served 

 to eject the water within when necessary 

 for ascending. At the top there was like- 

 wise an oar for ascending or descending, 

 or continuing at any particular depth ; 

 a water-gauge or barometer determined 

 the depth of descent, a compass directed 

 the. course, and a ventilator within sup- 

 plied the vessel with fresh air when on 

 the surface. 



The entrance into the vessel was ellip- 

 tical, and so small as barely to admit a per- 

 son. This entrance was surrounded with 

 a broad elliptical iron band, the lower 

 end of which was let into the wood, of 

 which the body of the vessel was made, 

 in such a manner as to give its utmost 

 support to the body of the vessel against 

 the pressure of the water. Above the 

 upper edge of this iron band there was a 

 brass crown or cover, resembling a hat 

 with its crown and brim, which shut wa- 

 ter tight upon this iron band. The crown 

 was hung to the iron band with hinges, 

 so as to turn over sideways when open. 

 To make it perfectly secure when shut, 

 it might be screwed down upoii the 

 band by the operator, or by a person 

 without. 



There were in the brass crown three 

 round doors, one directly in front, and 

 one on each side, large enough to put the 

 hand through : when open they admitted 

 fresh air; their shutters were ground per- 

 fectly tight into their places with emery, 

 hung with hinges, and secured in their 

 places when shut ; there were likewise 

 several small glass windows in the crown, 

 for looking through and admitting light 

 in the day time, with covers to secure 

 them. There were two air-pipes in the 

 crown. A ventilator within drew fresh 

 air through one of the air-pipes, and dis- 



charged it into the lower part of the ves- 

 sel ; the fresh air, introduced by the ven- 

 tilator, expelled the impure light air 

 througJi the other air pipe. Both air 

 pipes were so constructed, that they shut 

 themselves whenever the water rose near 

 their tops, so that no water could enter 

 through them, and opened themselves 

 immediately after they rose above the 

 water. 



The vessel was chiefly ballasted with 

 lead fixed at the bottom ; when this was 

 not sufficient, a quantity was placed with- 

 in, more or less, according to the weight 

 of the operator ; its ballast made it so 

 stiff, that there was no danger of its over- 

 setting. The vessel, with all its appen- 

 dages, and the operator, was not of suffi- 

 cient weight to settle it very low in the 

 water. About two hundred pounds of 

 the lead at the bottom for ballast could 

 be let down forty or fifty feet below the 

 vessel ; this enabled the operator to rise 

 instantly to the top of the water in case 

 of accident. 



When the operator would descend, he 

 places his foot on the top of a brass valve, 

 pressing it, by which he opened a large 

 aperture at the bottom of the vessel; 

 through this the water entered at his 

 pleasure ; when he had admitted a suffi- 

 cient quantity, he descended very gra- 

 dually ; if he admitted too much, he 

 ejected as much as was necessary to ob- 

 tain an equilibrium by the two brass forc- 

 ing pumps which were placed at each 

 hand. Whenever the vessel leaked, or he 

 would ascend to the surface, he also made 

 use of these forcing pumps. When the 

 skilful operator had obtained an equili- 

 brium, he could row upward or down- 

 ward, or continue at any particular depth, 

 with an oar placed near the top of the 

 vessel, formed upon the principle of the 

 screw, the axis of the oar entering the 

 vessel; by turning the oar one way, he 

 raised the vessel ; by turning it the other 

 way he depressed it. 



A glass tube, eighteen inches long and 

 one inch in diameter, standing upright, 

 its upper end closed, and its lower end, 

 which was open, screwed into a brass 

 pipe, through which the external water 

 had a passage into the glass tube, served 

 as a water-gauge or barometer. There 

 was a piece of cork, with phosphorus on 

 it, put into the water-gauge. When the 

 vessel descended, the water rose in the 

 water-gauge, condensing the air within, 

 and bearing the cork with its phosphorus 

 on its surface. By the light of the pnos- 

 phorus, the ascent of the water in the 



