I V I N 



[.nlhrrdi- 



.m,c chc-t. 



Mn. it H rendered unfit for the iam me again, lu-ii.- taken 

 ^V"^ from it. by iu circulation through the pipes, t. the sides 

 of whirl) !t would adhere, and leave the air as free a* 

 before." We h;ivi- gi\m this idea, to shew tin- -t..t ( - of 

 philoiophy in Borelli's time, when it was not generally 

 known that the air was rendered unfit for respiration, 

 by the abstraction of the vital principle or oxygen, but 

 mpuoeed that it became impure from the addition of 

 noxious vapours. To some, the real fact had been 

 known long before ; for a famous Knglish projector, 

 DnbcO'i Cornelius Drcbcll, in the reign of King James I. made 

 ""riae a submarine veM*l, which would carry twelve rowers 

 * beaide* the passengers, and could.be rowed under water. 



It was tried in the river Thames. Mr Boyle, from 

 whom we have this account, assures us that he learned 

 from a phyician, who married DrclM'll's daughter, 

 that he carried a liquor in the vessel which supplied tin- 

 place of fresh air. When the air in the submarine boat 

 was rendered foul by the breath of the company, by 

 opening the vessel containing this liquor, he could 

 speedily restore to the air such a portion of its vital parts 

 as would make it serve agiu'n for some time. The se- 

 cret of this preparation Urehell would never disclose to 

 above one person, who himself assured Mr Boyle what 

 it was ; and if the above account of its properties be 

 strictly true, we have much to regret in the loss of it, 

 for it would be no less valuable in working mines where 

 the air is bad than in diving. 



Mr Martin, in his Phi/otop/iia Britannicti, mentions 

 an apparatus contrived by an Englishman, consisting of 

 strong leather, so prepared that no air could pass 

 through. It fitted hit arms and legs, and had a glass 

 window placed in the fore part of it. When dressed 

 in this apparatus, which was large enough to contain 

 half an hogshead of air, he could walk on the ground 

 at the bottom of the sea, and enter the cabin of a sunk 

 ship to take out the goods. The inventor is said to 

 have himself used this machine very extensively in re- 

 covering wrecks, and with such great success as to have 

 acquired considerable property by it. We are not in- 

 formed of the depths to which he descended. 



Mr Klingert, whose water armour we have already 

 tiriaf chat, described, also invented a diving chest, to be used 

 along with the armour when employed in great depths. 

 He there found the original construction impracticable, 

 because of the difficulty of breathing through a long 

 pipe, and the great inconvenience of managing it at the 

 bottom, or when the diver wished to rise to the surface. 

 His machine consisted of a hollow cylinder, termina- 

 ted by two frustums of cones, framed of staves, and 

 bound with hoops in the manner of casks, but exceed- 

 ingly strong, and covered with a varnish, to render it 

 perfectly tight. On the outside of the machine is a 

 stage for the diver to stand upon, who is furnished with 

 all the harness and pipe* before described ; and the ends 

 of the pipes being conducted to the machine, he obtains 

 his supply of air from it as long as it is sufficiently pure. 

 This time he estimates at two hours, when the machine 

 in made to contain 58 cubic feet of air. When it de- 

 , the axis of the machine is in a vertical position, 

 so ballasted with lead as to be in no danger of 



_, ing. The breathing pipe to supply the diver, 



ommunicatr* with tin- low cst part of the machine ; and 

 tfce other, or pipe of escape, is screwed into the top : by 

 this means, the air is not rendered so foul by the mix- 

 ture of that which haspasned through the lungs of the 

 diver, because the latter being heated, and thus render- 

 ed specifically lighter, floats on the fresh air, and occu- 

 pies the upper part of the machine, where it is introdu- 



ced by the waste pipe; and the fresh ir which remains rnvlnp. 

 in the" lower part of the machine, is drawn off by the "<" 

 breathing pil>v as the diver requires it. Hy thisineans 

 nil the contained air pastes gradually through the lungs 

 and when it is consumed the diver must ascend with 

 his machine, nd IK- conveyed to the ship or boat in at- 

 tendance. By means of a rope applied to the upper part 

 of the machine, it is then drawn out of the water, thr 

 pipes unscrewed, and by blowing fresh air with a pair of 

 U-llow -, at one aperture', the foul air is driven out lit the 

 other, and the machine prepared for another deseent. 



The diver has the power of .trending or descending i t han * 

 with the imchinc at pleasure, without being dependent pump, 

 iiix.n those in the boat, by means similar to the air 

 bladder of fishes. Thus the ballast is so adapted to ih - 

 si/.e of the machine, as to make it sink so tar that 

 ,i cubic foot of it remains above water. In this st.itr, 

 an additional weight of 100 pounds will d.-prcss it be- 

 low the surface, or make it sink to the bottom, 

 effect of adding extra weights is produced, by diminish- 

 ing the volume of contained air, by condensing it into 

 a smaller spnce. To accomplish this, a large cylinder 

 is applied in the bottom of the vessel, and provided 

 with a piston, which, by a rack and pinion, can be 

 moved from one end of the cylinder to the other, when 

 the diver turns a handle, coming through the side of 

 the machine, and communicating motion by a worm 

 and wheel to the pinion of the rack before mentioned. 

 The lower end of the cylinder is open to the water, and 

 the upper end opens within the machine ; therefore, 

 w hen the diver turns the handle in the direction to raise 

 up the piston in its cylinder, it necessarily diminishes 

 the bulk of the included air, and the machine will sink; 

 but on depressing the piston in the cylinder, it will as- 

 cend again. The inventor proposed to furnish the ma- 

 chine with two small oars to move it in the water, and 

 an anchor or grapnel to make it fast, whilst the diver 

 walks about on tile bottom, within the limits of the 

 length of the pipe, to examine sunk bodies, and discover 

 the best mode of raising them. To prevent danger 

 from any accident happening to the machine, the diver 

 is to be provided with the means of quickly detaching the 

 pipes from the machine, and retaining a sufficiency of 

 air in the armour to carry him to the surface, when he 

 throws off the weights suspended from his girdle. Mr 

 Klingert also mentions a lantern of his invention, which and lantern. 

 may be very useful to a diver at the bottom of the sea. 

 The principles of its construction he keeps secret, but 

 asserts that it is very simple, and that a candle inclosed 

 in one of them will burn in every kind of air in mines 

 and pits, where all other lights are extinguished, 

 contains a space equal to a cubic foot, and 1 

 will burn without any addition of fresh air from with- 

 out for 2 or 3 hours. 



Plate CCXXXI. Fig. 4, represents a diving machine, MrHowc ., 

 invented in 1753 by Mr Howe. It is a trunk or hollow j^g 

 copper vessel aa BD, soldered or rivetted together with che*. 

 strength proportioned to the depth of water where it is p LATE 

 to be fixed. It contains the diver's Ixxly, and also a CCXXXf. 

 sufficiency of air for the time he intends to dive. He <* 

 enters with his feet first at the open end a a, which i; 

 then closed by a lid or cover screwed on, by a number 

 of screw bolts passing through the flanches n, a. 

 vessel is bent at D, for the bearing of the diver's knees, 

 and hasasufficiency of leaden ballast at < l.to sink it m the 

 right position. l>b are two hoops surrounding it, which, 

 at the same time that they strengthen it, afford points 

 of suspension by a bar d, which is attached to them, 

 and i* pierced with several holes to admit a span upon 



