DIVING BELL. 



pressure, and the sleeves from being 

 thrust into the engine ; d d represents a 

 cover to fit the head of the engine, fas- 

 tened down with screws, and leather be- 

 tween the borders, so as to prevent leak- 

 ing in any depth of water ; a b repre- 

 sents a plate of lead, to be fastened be- 

 fore the engine, in a straight line, pass- 

 ing between the arms, not only as a pro- 

 per weight to sink the engine, but as a 

 balance thereto ; whereby the diver will 

 always be kept in a proper posture for 

 working, and the more so by means of a 

 block, or cradle, supposed to be fastened 

 over the lead, by which means the di- 

 ver has not only the power of handling 

 what is at the bottom, but may at any 

 time rest his arms from work ; g is the 

 engine-rope, by which it is let down and 

 hauled up again from the bottom ; z y u 

 is called the life-line, with a knot at y y so 

 as the handle at z may always remain at 

 a due distance for the diver to take 

 hold thereof, in order to give any notice 

 to the persons above, as, by agreement, 

 by giving a certain number of pulls, or 

 sudden twitches, which is immediately 

 felt by the person that holds the line. The 

 diver can tarry under water at least half 

 an hour at one time, without the help of 

 pipes, or any other air than what the en- 

 gine contains. At i and -w are two brass 

 screw caps, or plugs, both which are to 

 be opened as soon as the diver gets from 

 the bottom to the water's surface, in or- 

 der to give him fresh air by help of a pair 

 of bellows blowing at the latter ; at which, 

 when the engine leaks, we likewise 

 pump out the water. In deep water 

 the diver is forced to make use of a sad- 

 dle on his back, with a ridge touching 

 the upper part of the engine, whereby 

 he can keep his arms at a due distance 

 out of the engine, which otherwise 

 would be thrust in by the column of 

 water pressing thereon equal to the 

 weight thereof. 



The subject of submarine navigation 

 was largely and pleasantly descanted upon 

 by Mersennus, in his " Tractatus de 

 Magnetis Proprietatibus," and Bishop 

 Wilkins has given a chapter at some 

 length on the subject, in his " Mathe- 

 matical Magick," (ed. 1648) where he 

 affirms that Cornelius Dreble has proved, 

 beyond all question, that the contrivance 

 is feasible, by the experiments he made 

 in England. The chapter of Wilkins is 

 entertaining, for a sort of visionary faci- 

 lity with which he removes the difficul- 

 ties, and enumerates the benefits, of these 

 submarine enterprises. For letting out 



and taking in such things as the nature 

 of the voyage may require, he reconi' 

 mends bags, or flexible tubes, some- 

 what resembling the scupper bags of 

 ships. The progressive motion may, he 

 observes, be produced by fins or oars, 

 which will operate with ease when the 

 vessel is truly equipoised ; and if swift- 

 ness should not be obtained, lie sup- 

 poses the observations ami discoveries 

 to be made at the bottom of the sea 

 would abundantly recompence for the 

 defect. The greatest difficulty, in his ap- 

 prehension, would be, the necessity of 

 renovating the air for respiration and 

 combustion ; for remedying which, be- 

 sides the probability that custom may 

 render men capable of living in air of in- 

 ferior purity, he has several philosophi- 

 cal views and projects. The conveni- 

 ences and advantages he enumerates are, 

 1. Privacy ; as a man may thus go to any 

 part of the world invisibly, without being 

 discovered or prevented. 2. Safety from 

 the uncertainty of tides and tempests 

 that vex the surface ; from pirates and 

 robbers ; and from the ices that so much 

 endanger other voyages towards the 

 poles. 3. It may be of use to undermine 

 and blow up a navy of enemies. 4. Or 

 to relieve a blockaded place. 5. And as 

 the prospect enlarges in the mind of our 

 author, he proceeds to contemplate the 

 unspeakable benefit of submarine disco- 

 veries. Experiments on the ascent and 

 descent of submerged bodies ; the ex- 

 ploration of the deep caverns and pas- 

 sages, and the waters of the ocean ; ob- 

 servations" on the nature and kinds of 

 fishes, with allurements, artifices, and 

 treacheries, which may successfully be 

 practised during so familiar a residence 

 in their territories ; the food and oil they 

 may afford ; the probability of fresh 

 springs for a supply of water at the bot- 

 tom of the sea ; the facility of recovering 

 submarine treasures, whether lost or na- 

 turally produced beneath the ocean ; and 

 last ofall he adds, that 



" All kinds of arts and manufactures may 

 be exercised in this vessel The obser- 

 vations made by it may be both written, 

 and, if need were, printed here likewise. 

 Several colonies may thus inhabit, hav- 

 ing their children born and bred up 

 without the knowledge of land, who 

 could not chuse but be amazed with 

 strange conceits upon the discovery of 

 this upper world." 



The only modern instance of actual 

 submarine navigation is that of Mr. Bush- 

 nel, recorded in the Transactions of the 



