DIVING BELL. 



ground at each going down, and at last fell in with n 

 stump of the wreck, sunk five fathoms deep at low wa- 

 ter tc .i level with tlii- soft bed of the river, which is 

 composed of a light sand intermixed with shells. The 

 principal part* of this wreck were supposed to liavc been 

 carried away by an immense body of ice the year be- 

 fore. I Ie fniiiid, that the muddiness of the river occa- 

 sions a darkness at only two fathoms from the surface 

 that cannot be described ; and from the snialhu -s <>i' 

 his machine, which contained only forty-eight English 

 gallons, it was impossible to have a candle burning in 

 it, which would consume the air too quickly for any 

 man to be able to work, and at the same time pay at- 

 tention to receiving the necessary supplies of air. 



These trials were only preparatory to his views at 

 the Scares, hoping to acquire experience, which would 

 enable him to surmount the dangerous difficulty of the 

 unequal rocky bottom which he expected to meet with ; 

 but in the preceding trials, and different alterations of 

 the machinery, so much time had been lost, that the 

 weather became stormy, and he was obliged to wait at 

 Bamborough Castle some time, till the weather became 

 more favourable. He then sailed to the Scares, with his 

 '*?'***'* brother, three sailors, and two pilots. It was four in the 

 afternoon, about high water, when he went down at 

 a small distance from the place, where he judged 

 the wreck to lie. The depth was about ten fa- 

 thoms. He fortunately alighted on n flat part of the 

 rock, within a small space of a dreadful chasm, and had 

 just gone two steps with his machine, when the terror 

 of the two pilots was so great, that, in spite of his bro- 

 ther, they brought him up very precipitately, before he 

 had in any degree examined around him. On coming 

 into the boat, they remonstrated on the danger of the 

 machine being overturned either on the wreck or the 

 rocks, and also on the impossibility of raising any of 

 the weighty goods with so small a purchase in an open 

 boat, and in a place where, at this season, no large 

 vessel would venture to lie, ns the nights were then *o 

 long, and only two passages for a small vessel to run 

 through, in case of a gale of easterly or southerly wind; 

 one of the passages being extremely narrow, and both 

 of them dangerous. 



Convinced from this, says Mr Spalding in his ac- 

 count, " that with an open boat nothing could be ac- 

 complished, and that, except in June and July, no 

 man would risk himself with me in a sloop, to continue 

 a few days and nights at anchor there, I was obliged 

 to abandon my project ; yet I determined to take a 

 to a Dutch view of the guns of a Dutch ship of war lost in the year 

 hip. 1704, and as they lay two or three miles nearer the 



land, I could execute this design with less difficulty, 

 especially as the weather continued still favourable. 

 Having procured all the intelligence possible, we went 

 to the place, where I went down four different times, 

 but could find no marks of any wreck, notwithstanding 

 my walking about in five and six fathoms water, as far 

 as it was thought safe to allow the rope to the liell, con- 

 tinuing generally twenty minutes each time at the lx>t- 

 tnin. On this orca-i( in I was obliged to carry a cutting 

 hook and knife, and clear away the sea weeds, w liicli at 

 this place are very thick and strong ; without this me- 

 tliod I could not move about. At the fifth going down, 

 each trial being in a different place, I was agreeably 

 surprised to find a large grove of tall weeds, all of them 

 from six to eight feet high, with lar;;e tufted tops, imt- 

 ly in regular ranges, ns far as the eye eouKl reach, a 

 variety of small lobsters and other shell fish swimming 

 About in the intervals." He then di-covcred the p' 



where one of the cannons lay ; but was tn much 

 liau-tcd. bv having been down nt intervals for near 

 tlirec hours, to attempt bringing it up. 



In these descents, Mr Spalding found out two very 

 serious dangers attendant on the use of the l>ell, in Dr 

 Halley's plan. The^e are, h'irsl. l!y \)r Halley's construc- 

 tion, the sinking or rising of the bell depends entirely 

 upon the people who are at the surface of the water ; 

 and as the bell, even when in the water, has a very 

 considerable weight, the raising of it not only requires 

 a great deal of lulxnir, but there is a possibility of the 

 rope by which it is raised breaking ; and thus every 

 person in the bell Would inevitably perish. Secondly, 

 As there are, in many places of the sea, rocks which 

 lie at a considerable depth, the figure of which cannot 

 possibly be perceived from above* there is danger that 

 some of their ragged prominences may catch hold of 

 one of the edge* of the l>ell in its descent, and thus over- 

 set it before any signal can be given to those above, 

 which would infallibly be attended with the destruction 

 of the people in the bell, especially as it must always 

 be unknown before trial what kind of a bottom the sea 

 has in any place. 



Mr Spalding made such additions to Dr Halley's bell 

 as completely obviated these defects. They will be ren- 

 dered evident from the following description: ABCD, 

 Fig. (i, is the body of the bell, made of pipe staves, five 

 feet long, five feet diameter at bottom, and two and a 

 half at top. It is suspended by four ropes e, e, attach- 

 ed to hooks, fastened on the sides of the bell, and meet- 

 ing at the toj) where the hook of the great rojie Q takes 

 them, c, c, are the ballast weights, suspended from 

 hooks on the outsides. These keep the mouth of the 

 bell always parallel to the surface of the water, whether 

 the machine, taken all together, is lighter or heavier 

 than an equal bulk of the fluid. By these weights alone, 

 however, the bell would not sink ; another is there- 

 fore added, represented at L, and which can be raised 

 or lowered at pleasure, by means of a rope passing over 

 the pulley a, and fastened to one of the .sides of the bell 

 at M. As the bell descends, this weight, called by Mr 

 Spalding the balance weight, hangs down a consider- 

 able way below the edge of the bell. In case the edge 

 of the bell is caught by any obstacle, the balance weight 

 is immediately lowered down, so that it may rest upon 

 the bottom. By this means the bell is lightened, so 

 that all danger of oversetting is removed ; for being 

 lighter without the balance weight than an equal bulk 

 of water, it is evident that the bell will rise as far as the 

 length of rope affixed to the balance weight will allow 

 it. This weight, therefore, will serve as a kind of an- 

 chor to keej) the bell at any particular depth which the 

 divers may think necessary ; for being let down to the 

 bottom before the bell descends, the diver by balding 

 the rope will descend, though he does not rnise the 

 weight. Instead of wooden seats or stage used by Dr 

 Halley, Mr Spalding made use of ropes, suspended by 

 hooks b,b across the bottom of the bell; and on these 

 ropes the dixcrs may stand without any inconvenience. 

 Two windows, made of thick strong glass, are fixed near 

 the top of the bell, for admitting light to the divers. 

 T, \ represent tiie two air casks, with theirtackle; and 

 OCP the flexible pipe, through which the air is admit- 

 ted to the bell : the casks contain 1-0 gallons each. In 

 the ascent and descent of this cask, the end of the pipe 

 i- guided by the lines M, extended from the bell to Un- 

 ship above. The ends of the pipes are kept down by 

 a small weight appended, an in Dr Halley's machine; 

 or what is better, they may liave cocks as at P. H i- a 



nrfecuof 

 I ir Hallry'i 



Mr Spl- 

 ding's bell. 



Pi .\ -i F. 

 i i \\.\II. 

 Fig. 6. 



Balairt 



weight. 



Air barrels 



