694 



DlVINCi-BELL DIVISIBILITY. 



from the end of the barge, which would increase the 

 quantity of light admitted into the bell. From the 

 top of the bell, then- proceeds aho-e or leather pipe, 

 which is led up to the deck, where it communicates 

 with two forcing pumps, by which means fresh ah- is 

 constantly issued into the bell, which air by its ant- 

 sure, dhfHOH the water in the cavity A, and allows 

 the divers to carry on their operations. The bell 

 I - t'niir -.ides, beta* M'niewhat larger at the bottom 

 liianthetop, and (he metal being thicker towards 

 the mouth, in order to counteract any tendency that 

 the lx-11 miht have to overset. The area of the 

 bell at the oath is 5 feet 7 inches, by 3 feet 9 

 inches, and at the top 5 feet 2 inches, by 3 feet 7$ 

 indies ; the height of the top above the mouth is 

 about 6 feet. To the top is attached a strong ring, 

 i., in which the tackling used for lifting stones is 

 attached when these are lifted in the bell ; but some- 

 times these are taken up through an opening at the 

 one side of the bell, as may be seen in fig. 1. ; and in 

 order that these should press easily up, there is a hook 

 on the right hand side of the bell, and near the botr 

 torn, by which the bell may be drawn aside, in order 

 that more space may be left for raising the stones. 

 These stones are raised by a crane, which may be 

 seen at u-, in the end elevation, fig. 2, the tackling of 

 which passes over the framework above. At e, is 

 seen the crane which raises or depresses the bell, and 

 at K, the pumping apparatus. These pumps have a 

 bore of 8 indies diameter, with a stroke of about 

 10 feet, making 20 strokes per minute. The whole 

 length of tlie barge which carries the diving apparatus 

 is 46 feet, and breadth about 18. To the frame 

 work is attached a signal ball, n, which is raised when 

 tlie bell is under water, to warn the masters of steam 

 vessels to stop the engine before they approach the 

 barge, so that the divers may not be interrupted by 

 the agitation of the water. 



Mr Deaue has recently contrived and employed 

 an ingenious diving apparatus, which lias been success- 

 fully employed, and of which, through his kindness, 

 we are enabled to give tlie following particulars. The 

 head of the diver is covered by a helmet of thin sheet 

 copper, G, fig. 4, plate XXVII, large enough to admit 

 of the easy motion of the head, and capable of con- 

 taining between 6 and 8 gallons of air. The helmet 

 comes pretty far down on the breast and back, and 

 has in front three eye holes, covered with glass pro- 

 tected by brass wires. The copper helmet is attached 

 to a water-proof canvass jacket by means of rivets, F, 

 so tightly fixed that no water can be introduced to the 

 body of the diver. The junction of the helmet and 

 jacket is stuffed, so that it may clasp the shoulders of 

 the diver firmly. A leather belt, E, passes round the di- 

 ver, to which are attached two weights, one before and 

 the other behind, each weighing about 40 ll;s. These 

 weights, one of which is seen at C, are attadied in 

 order that the diver may descend with facility ; but in 

 case of any accident occurring when he is at the 

 bottom, the belt is fastened with a buckle in front, 

 which he can instantly unloose, and rise to the sur- 

 face after the dropping of the weights. The diver is 

 supported with fresh air by means of the flexible 

 water-proof pipe, A, which enters the back of the hel- 

 met, and communicates with an air pump wrought 

 above in the barge from which the diver descends. 

 The tube passes under the left arm of the diver, and 

 turning upwards enters the back of the helmet, being 

 so contrived that the fresh air is made to impinge 

 against the glasses, which in a great measure pre- 

 vents their being dimmed by tlie moisture of the 

 breath. From the back part of the helmet there is 

 likewise led an eduction pipe, to allow tlie escape of 

 the breathed air. In order that the diver may give 

 notice to the attendants at the top when he requires 



a hook, tackle, bucket, or any difference in the sup- 

 ply of fresh air, he is furnished with a signal line, B, 

 which passes under his right arm. The diver de- 

 scends from the side of the vessel either by means of 

 a rope or wooden ladder loaded at tlie lower end, 

 (more frequently by the former) the weight being 

 kept at a height of about two feet from the ground. 

 When tlie diver descends to the bottom, the rope is 

 let down, so that it becomes slack, to prevent the 

 motion of the boat from obstructing him, and he car- 

 ries a line in his hand, that lie may, when necessary, 

 return to the rope. In order tliat the diver may be as 

 comfortable as possible under water, he puts on two 

 suits of flannel, above which he lias a complete dress 

 (in one piece, of Mackintosh's water-proof cloth). 

 The water-proof dress covers the body entirely, the 

 only apertures being at the neck and wrists. The 

 opening at the neck comes well up, and is tied round 

 tightly with a bandage, which contrivance, together 

 with the pressure of the air in the helmet, prevents 

 the water from entering tlie helmet, and the wrists 

 are likewise tightly bound with bandages. 'I he 

 diver is thus enabled to remain for five or six hours 

 at once under water, all the while perfectly dry, his 

 motion being rendered quite steady by heavy weights 

 attached to his shoes. 



With this apparatus, the ingenious and enterpris- 

 ing inventor has dived for several wrecked vessels 

 in the Western Highlands of Scotland, at Spithead in 

 England, on tlie coast of France, and, at Copcland 

 island, off Donaehadee, north-east coast of Ire- 

 land, at which latter place he has brought up 

 an immense number of silver dollars, several gold 

 coins, some bottles of wine covered with shell fish., 

 and many other curious and valuable articles, from 

 a vessel wrecked there more than thirty years since. 

 At the other places alluded to, he met with similar 

 success. Fig. 5 represents Mr Dean's diving at the 

 Royal George, which was sunk about forty years 

 since. 



DIVINING BS|D (virgula Mercurialis) is a rod 

 made with certain.superstitious ceremonies, either 

 single and curved, or with two branches, like a fork, 

 of wood, brass, or other metal. The rod is held in a 

 particular way, and if it bends towards one side, 

 those who use tlie rod believe it to be an indication 

 that there is treasure under the spot. Some publi- 

 cations respecting a, man who, in quite recent 

 times, pretended to Jbe able to discover water and 

 metals under the -ground by his feelings, attracted 

 much attention. See Campetti. 



DIVISIBILITY. The actual subdivision of 

 bodies has, in many cases, been carried to a prodigious 

 extent. A slip of ivory, of an inch in length, is 

 frequently divided into a hundred equal parts, which 

 are distinctly visible. But, by the application of a 

 very fine screw, 5000 equidistant lines, in the space of 

 a quarter of an inch, can be traced on a surface of 

 steel or glass with the fine point of a diamond, pro- 

 ducing delicate iridescent colours. Common writing 

 paper has a thickness of about the 500th part of an 

 inch ; but tlie pellicle separated from ox-gut, and 

 then doubled to form gold-beaters' skin, is six times 

 thinner. A single, pound of cottoq has been spun 

 into a thread seventy-six miles in length; and the same 

 quantity of wool has been extended into a thread of 

 ninety-five miles; the diameters of those threads being 

 hence only the 350th and 400th parts of an inch. 



But the ductility of some metals far exceeds that 

 of any other substance. The gold-beaters begin with 

 a riband an inch broad and 150 inches long, which 

 has been reduced, by passing tlirough rollers, to 

 about the 8COth part of an inch in thickness. This 

 riband is cut into squares, which are disposed be- 

 tween leaves of vellum, and beat by a heavy liam- 



