Pneumatics.

The Spring of the Air is most evicted

concerned in that Chirurgicai Operas 1

io#

Position and no other. In the Top' was fixed abut clear Glass D, to let in the Light from above; * (likewise a Cock, as at B, to let out the hot Ait ^ fhad been breathed; and below, at L M, was fi^ ^circular Seat for the Divers to sit on ; and lastly? ' f 0 (the Bottom was hung, by'three Ropes, a Stag®,the Divers to stand upon to do their Business. 7 .Machine was suspended from the Mast of a Ship ^Sprit, which was sufficiently secured by Stays t°-Mast-head, and was directed by Braces to carry it jpboard clear of the Side of the Ship, and to bring

again.

tw

3. To supply the Bell with Air underWater,Barrels, such as C, of about 63 Gallons each, ^made and cased with Lead, so that they might ‘ ^empty, each having a Hole in its lowest Part to l^jrthe Water, as the Air in them is condensed infestDescent, and to let it out again when they were di ' ^

up full from below. And to a Hole, in the Top

Barrels, was fixed a Hose or hollow Pipe, well P 1 ^), t°with Bees-Wax and Oil, which was long enoV&fall below the Hole at the Bottom, being lunk c (a Weight appended, so that the Air in thePart ®f the Barrels could not escape, unless theEnds of these Pipes were first lifted up. -f y

4. These Air-Barrels were fitted with Tackle,per to make them rife and fall alternately, stk e .ybBuckets in a Well; in their Descent, they were db eby Lines fastened to the under Edge of the Bell \,jMan standing on the Stage to receive them, ^ . o>taking up the Ends of the Pipes above the S ur *Lf i<*the Water in the Bell, gave Occasion for the

the Barrels to force all the Air in the upper

, „. ...by a

the Bell, while it entered below, and filled the

And as soon as one was discharged, by a Sig lia ^it was drawn up, and the other descended, to hefor Use.