relative to Black, Watt, and Cavendish. 493 



would generate an air ; viz. oil of tartar and vitriol, spirit of 

 wine and turpentine, &c. Colonel Blunt added that oysters 

 pounded and put into wine would make it ferment." 



"On the 15th of March, the experiment of generating air 

 was made in this manner. There was taken a common glass 

 phial with two pipes, and some pounded oyster-shells and 

 aquafortis ; and as soon as the aquafortis was by one of the 

 pipes poured in upon the powder, and the hole stopped with 

 a piece of hard cement, the ebullition caused by the corrosion 

 of the shells by the aquafortis did in a very little time blow up 

 the bladder (tied on the other pipe) so as to swell it with air, 

 very plump; which expansion remained till the rising of the So- 

 ciety, when the vessel in that posture was locked up in the box 

 of the watch, to remain there until the next assembly." Dr. 

 Wren made use of this experiment — " to explicate the motion 

 of the muscles by explosion." " There was also taken a bottle 

 containing strong ale that had been bottled awhile ; and over 

 the bottle's mouth was tied an ox-bladder out of which the 

 air was squeezed ; after which by loosening the cork by de- 

 grees the air was blown out into the bladder by the expansion 

 of the fermenting liquor within, and the bladder was almost 

 half-filled with an aerial spirit generated by the working 

 liquor." Mr. Boyle, bearing perhaps in mind his anecdote of 

 Drebell's submarine vessel, suggested that the experiment was 

 capable of improvement for the producing of air under water, 

 and mentioned coral, or oyster-shells, and distilled vinegar, as 

 wholesome substances for that purpose: he moved that an 

 animal might be put into the receiver of his engine and the 

 air exhausted till the creature grew sickly, and that then some 

 new air might be produced in the receiver by a contrivance 

 of making distilled vinegar work upon coral, to see whether 

 by this means the animal could be revived. Dr. Wilkins 

 moved that at the next meeting the air generated by the mix- 

 ture of aquafortis and the pounded oyster-shells might be 

 blown into a dog's or cat's mouth, to see what would be the 

 effect thereof." 



" On the 22nd of March there were two experiments made 

 for the finding out a way to breathe under water, useful for 

 divers. The first was made by putting a bird into a rarefying 

 engine, and with it a glass bottle with distilled vinegar and 

 pounded oyster-shells, which whilst the vinegar is dissolving 

 them affords a stream supposed to be a kind of new air fit for 

 respiration. The bottle was also close stopped with a cork, 

 so ordered that by pulling the stop-cock placed on the top of 

 the receiver, the cork might, by turning it, be pulled out 

 without admitting an ingress of the external air into the re- 



