DIVING BELL. 



17 



DivingBeD. divers find the direction in which they wish to be mo- 

 "Y""' ved, and can communicate orders to those above by a 

 signal line tied below to the bell, and going up to the 

 ship, when some intelligent person must hold it in his 

 hand, to feel the signals which the divers make by 

 snatching it. To avoid the danger of mistakes, the 

 signification of these signals should be painted round 

 the inside of the bell. Thus one snatch signifies, make 

 the bell rope fast to keep it stationary ; two, means to 

 descend ; three, to ascend ; four, to the north ; five, to 

 the south ; six, to the east ; seven, to the west. A board, 

 with duplicates of all these, is to be kept near the per- 

 son above, who will be very conveniently situated a- 

 stride upon the yard-arm, so as to be directly over the 

 bell, and will there have a view of all the ship's com- 

 pany, as well as the bell under water. The signal line 

 should be a deep sea lead-line, such as seamen use to 

 sound in deep water, with the usual marks to know the 

 depths. These will shew how far the bell is below the 

 surface, and will be attended with the advantage of ena- 

 bling the divers to denote the distance they wish to 

 move, ascend or descend. Thus if they snatch twice, 

 it denotes to descend ; and immediately after if thoy 

 gently pull down two fathoms of the line, which the 

 man above must give out, and take notice of the quan- 

 tity, he will find they wish to descend two fathoms 

 lower ; the same of ascent, or progression sidewise, in 

 any direction by the compass. To avoid confusion or 

 delay, those of the ship's crew who are to haid the ropes 

 for motion, ascent, and descent of the bell, should in all 

 things be under the command of this man, and no other ; 

 but another should undertake the command of the peo- 

 ple who manage the supply of air. He may be placed 

 with great advantage in a boat, where, if he has another 

 to assist him, he may be able to do the whole ; for the 

 barrels weigh very little in descending, and in ascend- 

 ing only as much as their bulk of water, which need 

 not be above 20 gallons. Indeed as Mr Spalding says, 

 one barrel of 30 gallons would be sufficient ; and we 

 think it woidd be more easily managed than two small- 

 er ones. 



The boat should have a piece of timber projecting 

 several feet over her stem or side, in the manner of 

 a ship's cat-head, or rather of an anchor boat, with 

 sheaves in it at the end for conducting the rope for the 

 air-barrel to a small roller with a winch, by which it is 

 drawn up with very little labour. 



The upper end of the leading line for conducting the 

 air pipes down to the bell, should be led through a 

 sheave in the timber, at a proper distance from the 

 others, and should be held by the person above men- 

 tioned, who must take care to keep it always tight, 

 giving it out when the bell descends, and taking it in 

 when it is drawn up. 



If the divers have any directions to give concern- 

 ing the supply of air, they should do it by snatch- 

 ing this leading rope, and not the signal line, because 

 the orders will then be sent to the proper person, viz. 

 he who commands the boat. Thus his man winds up 

 the barrel, till it comes above water, and fills with air, 

 by the water running out at the open bung-hole in the 

 bottom ; then he lets it down again full of air, and the 

 end of the flexible pipe is guided by the thimble run- 

 ning down the guide-lino till it comes to the bell, where 

 one of the divers takes it in, and opens the cock in the 

 top of the bell to let out the hot air, till he sees the wa- 

 ter rise in the bell to certain marks, by which he knows 

 he has let out the exact quantity of air which the air 



VOL. VIII. PART I. 



Air tackle. 



Boat. 



Air pipes. 



barrel will replenish. As soon as the barrel has descend- Diving Bell, 

 ed below the level of the surface of the water in the bell, v v' 

 he opens the cock in the end of the flexible pipe to ad- 

 mit the air from the barrel ; but he must not do this 

 before the barrel has become lowest, lest the air should 

 take a contrary passage, and issue through the pipe 

 from the bell into the barrel, and perhaps escape from 

 its bottom into the sea. The cock at the end of the 

 pipe is likewise very useful to admit the air gradually, 

 lest by entering the bell, and suddenly displacing that 

 quantity of water, which was just before gradually ad- 

 mitted when the hot air was let out, it should cause the 

 bell to heave up. When the bell rests upon the ground 

 or the deck of a ship at the bottom, it will be necessary 

 to draw it up a little, to allow the air barrel to go low- 

 er and get the air into it ; it will give a great facility 

 to this, if the bell is made as above described, with 

 pumps and a chamber above : then if this let out so 

 much air from it as will make the bell, without its 

 ballast or anchor weight, lighter than water, the divers; 

 by letting out the rope of the balance weight, may suf- 

 fer the bell to rise 3 or 4 feet without waiting to give 

 orders to those above : the air being thus introduced 

 from the barrel into the bell, they return the air to the 

 chamber by the pumps; and if this does not cause it to 

 descend, they haul it down again by the balance weight, 

 then giving a snatch to the guide rope, the man in the 

 boat feels it, and knows he is to haul up the air barrel 

 to refill it with air. 



To proceed with advantage, two divers should de- Form of the 

 scend together, as they will then be able to manage with bell. 

 more confidence and expedition than if there was only 

 one. The principal diver must be a man possessing 

 great intrepidity and presence of mind, that he may pro- 

 ceed calmly to effect his purpose: He should be perfect- 

 ly acquainted with every thing belonging to the bell, 

 and the principles of hydrostatics on which it acts, so 

 as to have resources within himself for all that may 

 occur ; his companion should be completely under his 

 direction to execute his orders, and should be an ac- 

 intelligent man, well acquainted with the manage- 

 ment of the air barrel and the balance weight, which 

 are to be his chief occupations, unless when his prin- 

 cipal has other work for him to do, such as fastening 

 ropes to the goods, and assisting in cuttingaway the decks 

 of the wreck. For these purposes, the bell should be 

 well furnished with tools, that nothing may be found 

 wanting : a crow bar, two axes, proper saws, and a large 

 augur or centre bit are indispensible. One of the axes Their tools; 

 should be made exceedingly sharp, and kept for cut- 

 ting away ropes from the ship's rigging, which are very 

 dangerous to the bell in descending. These tools may 

 be kept at the sides of the bell, hung in loops formed 

 by leathern straps nailed upon the wood ; there should 

 likewise be provided a strong iron screw formed to 

 penetrate and hold in wood, with an eye at the end. 

 The divers should be dressed in thick flannel dresses, 

 with high water boots to keep their feet dry. Each man 

 may have a small rope made fast round his waist, and to 

 the top of the bell, with sufficient length to allow him to 

 work, but not to sink deep in the water if he falls. They 

 should stand upon ropes stretched across the mouth of 

 the bell, and have others fixed at a proper height to sit 

 upon ; also several fixed across the top of the bell, and 

 hanging down a little to take hold of, in case of accident, 

 as well as to obtain a hold for the purpose of lifting hea- 

 vy goods, when they are clearing the wreck. If they 

 intend to dive to the wreck of a ship, the diver should 



