DIVING BELL. 127 



leather, which acts as a valve and admits air. A strong leather hose 

 is screwed on to the external aperture, and from two holes near its sides 

 rise two strong chains, uniting in a ring, by which the whole machine 

 is to be suspended. In the top are cemented twelve thick lenses, to 

 admit light. 



At the ends of the bell are two seats, placed at such a height that the 

 top of the head is but a few inches below the upper part of the bell ; and 

 in the middle, about six inches below the lower edge, is placed a narrow 

 board on which the feet of the divers rest. On one side, nearly on a 

 level with the shoulders, is a small shelf with a ledge to contain tools, 

 chalk for writing, and a ring to which a rope is tide. A board is con- 

 nected with this rope, which is held by the man albove, who thus can 

 receive and reply to any message. On the top of the bell on the inner 

 side, it is usual to have some contrivance by which stone or other 

 bodies may be suspended from the bell. The leather hose is connected 

 with a double condensing pump, usually worked by four men. la order 

 to give motion to the bell, it is suspended by a windlass purchase tackle, 

 which is fixed on a moveable platform having four wheels ; the wheels 

 move along an iron railway, which is itself fixed on another platform, 

 having, by the same means, a motion in a direction transverse to the 

 former, at right angles to each other. Thus, by two iron railways 

 established on beams, and supported by piles, the lower being fixed in 

 the direction of the length of the wall, and the upper being on the lower 

 moveable plane, it is possible to give the bell any position which may 

 be required. 



Taking into account the extensive use of the diving bell for the last 

 fifteen years, at Plymouth and other sea ports, very few accidents have 

 occurred, and nothing but gross mismanagement and ignorance can now 

 occasion any, the mode of using them being so simple and well defined. 

 In fact, the workmen vie with each other who shall descend and work 

 for hours under water, as readily as above; immense treasure, &c. from 

 sunken vessels, has been recovered by means of the diving bill; as in the 

 case of the Thetis, &c. 



Mr. Babbage thus describes his feelings during a descent in a diving 

 bell at Plymouth, with Mr. Harvey. " To enter the bell, it is raised 

 about three or four feet above the surface of the water, and the boat in 

 which the persons who purpose descending are seated, is brought 

 immediately under it. The bell is then lowered so as to enable them to 

 step upon the foot board within it, and having taken their seats, the boat 

 is removed and the bell gradually descends to the water. On touching 



