DIVING. 



Piini- directed by a diver at the bottom to take up the goods 



^~ l ~~*' which are wanted, they are i-\tremely expedition-, in 



x ^l thrir operation. A, represents the rope let down into 



i , :. 



hop \VU- 



the water. It N attached to tin- )v>lt> or iron shank H, 

 which at the lower end has two arms abc, abc jointed 

 to it by a common centre pin f>. The lower ends c are 

 curved and form a clasp, to embrace the goods, while the 

 iipjn-r ends a are connected by links ad, ad to a socket 

 if, which -li.l. - upon 1!, and has a shackle with the 

 rope I) fastened to it. When these tongs are let down 

 i'\ tin- rop- A. the weight of the socket, and links ad, 

 dis|M>-c* tlu-rhiu- t.i o|iiMi a% in tin- Figure, and in this 

 state they are lowered or guided l.y the diver u]x>n the 

 goods to be recovered. The rope "D is then drawn up, 

 which raising the shackle, closes the claws upon the 

 object between them, and gripes them so hard that 

 they will seldom slip, because the greater the weight 

 the more powerfully they close together. If they tail 

 of catching it the first time, they may be opened again 

 by drawing the rope A, to make another trial. 



The experiment of Drebel's submarine boat, is not 

 the only attempt which has been made to navigate a 

 under water, without any communication with 

 those at the surface, but having the means of ascent 

 or descent, and making progress in any direction, in- 

 dependent of assistance from without. The celebrated 

 Bishop Wilkins, in his Mathematical Magic, dated 

 Iti 18, has given a chapter on the subject, in which, af- 

 ter referring to the successful experiments of Drebel, 

 he enumerates the benefits of these submarine enterpri- 

 zes, and with a visionary facility, which is truly enter- 

 taining, removes all difficulties. Thus for letting out 

 and taking in such things as the nature of the voyages 

 may require, he recommends bags or flexible tubes, 

 somewhat resembling the scruppcr bags of ships. The 

 progressiTe motion may, he observes, be produced by 

 fins or oars, which will operate with ease when the ves- 

 sel is truly equipoised ; and if swiftness could not thus 

 be obtained, still he supposed the observations and dis- 

 ies to be made at the bottom of the sea would 

 abundantly recompence for that defect. The greatest 

 difficulty, in his apprehension, would be in the neces- 

 oity of renovating the air for respiration and combus- 

 tion ; but for remedying this, he advances the proba- 

 bility, that custom may render men capable of living 

 in air of inferior purity ; arid besides, he has several 

 philosophical views and projects. The convenience and 

 nd vantages of submarine navigation which he enume- 

 rates, are, 1st, Privacy, as a man may thus go to any 

 part of the world invisible, without being discovered or 

 prevented. 2d, Safety, from the uncertainty of tides 

 and tempests which vex the surface, from pirates and 

 robbers, ami from the ices, which so much endanger 

 other voyages towards the poles. 3d, It may be of use 

 to undermine and blow up a navy of enemies, or to re- 

 a blockaded place. As the prospect enlarges in 

 the mind of our author, he proceeds to contemplate the- 

 unspeakable benefits of submarine discoveries; experi- 

 ments on the .-.-( ent and descent of submerged bodies ; 

 the exploration of the deep caverns and passages of the 

 water* of the ocean ; observations on the nature and 

 kinds of fishcx, with the allurements, artifices, and 

 treacheries which may bo successfully practised upon 

 them during so familiar a residence in their territories ; 

 the food and .il they may afford ; the probability of 

 fresh raring* for a itipply of water at the bottom of the 

 ea; the facility of recovering submarine treasures, 

 whether lort, or naturally produced beneath the ocean. 



The nearest approaches to realizing the bishop's in- 



genious conceits, besides the experiment of Debrel, wa* 

 made l>y Mr 1). Bushncll of Connecticut, in America, 

 who, in 1787, published a description of a submarine 

 vessel of his invention, in which it was found very prac- 

 ticable to travel under water ; though we cannot r< 

 that he tailed in his ultimate view of destroying ship- 

 ping, by approaching them under water, and fixing a 

 magazine to them, which was to explode at the expira- 

 tion of a certain time, after the diver left it detached 

 from his vessel. The whole invention displays very 

 great ingenuity and originality of idea. It is minutely 

 explained in the publication alluded to; but as it i~ ti* 

 complicated to be wholly understood from the verbal 

 description, without greater attention than ordinary 

 readers are disposed to give, our draughtsman ha-, pre- 

 pared two figures, viz. a vertical section, Plate Ct XXXI. 

 Fig. 9. and a horizontal section, Fig. 8, from the in- 

 ventor's description, which, except the letters of ret 'e- 

 rence, is as follows : The external shape of the subma- 

 rine vessel bore some resemblance to two upper tor- 

 toise shells of equal size joined together, the place of 

 entrance into the vessel being represented at A, Fig. 9, 

 by the opening made by the swell of die shells at the 

 head of the animal. The inside was capable of con- 

 taining the operator, and air sufficient to support him 

 thirty minutes without receiving fresh air. At the bot- 

 tom B, opposite to the entrance, was fixed a quantity of 

 lead for ballast. At one edge, which was directed be- 

 fore the operator, who sat upright, was an oar D, for 

 rowing forward or backward. At the other edge 

 a rudder E for steering. An aperture at the bottom, 

 with its valve a, was designed, to admit water for the 

 purpose of descending ; and two brass forcing pumps 

 b, l>, served to eject the water within when ncccs-ary lor 

 ascending. At the top, there was likewise an oar F 

 for ascending or descending, or continuing at any par- 

 ticular depth. A water gauge, or barometer d, deter- 

 mined the depth of descent, a compass directed the 

 course, and a ventilator within supplied the vessel with 

 fresh air when on the surface. The internal shape of 

 the vessel in every possible section of it, verged to- 

 wards an ellipsis as nearly as the design would allow ; 

 but every horizontal section, see Fig. H, although ellip- 

 tical, yet came as near to a circle as could be admitted. 

 The body of the vessel was made exceedingly strong; 

 and to strengthen it as much as possible, a firm piece 

 of wood H was framed parallel to the conjugate diame- 

 ter, to prevent the sides from yielding to the great pres- 

 sure of the incumbent water in a deep immersion. This 

 piece of wood was also a seat for the operator. The 

 entrance at A into the vessel was elliptical, and so small 

 as barely to admit a person. This entrance was sur- 

 rounded with a broad elliptical iron band ef, the lower 

 edge 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 \o-cl against the 

 pressure of the water. Above the upper edge of this 

 iron band, there was a brass crown, or cover Ci, resem- 

 bling a hat with its crown and brim, which shut water- 

 tight upon the iron band ee. The crown was hung to 

 the iron band with hinges, so as to turn over sidcw i-e 

 when opened. To make it perfectly secure when shut, 

 it might be screwed down upon the band by the ope- 

 rator, or by a person without. 



There were in the brass crown three round doors, one 

 at ./"directly in front, and one at g 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 



Diving. 



Pi. ATI 



trxxxi 

 Fig*. P, S>. 



Its part-- 



Bod)' of ihc 

 MM 



Entrance, 



mnl ill .or. 



