140 PHENOMENA OF THE UNIVERSE. 



put under the water, bears with it down to the bottom of 

 the vessel the air before contained in the platter ; but if, 

 with the like equilibrium, it be again taken out of the 

 water, you will find the air to have conveyed itself into not 

 much less space than it before filled. This will appear 

 from the colouring of the lip of the platter at the place 

 whither the water had ascended, and from which the air 

 received itself within. 



In a bed-room, if a window be left open when the wind 

 blows, if there be no other vent, it is not very much felt 

 (unless it be violent), since it is not received by the body of 

 wind which had filled the room, and was somewhat con 

 densed by the first gentle wind, and afterward does not 

 admit of condensation ; but as soon as a vent is given, it is 

 then manifestly perceived. 



For the more comfortable continuance of workmen under 

 water, it has been thought that a large hollow vessel might 

 be constructed of metal, or of some other kind of material, 

 to be let down to the bottom of the water ; that it might be 

 sustained by a tripod, with the feet affixed to the brim of 

 the vessel, and the feet to be a little less than the human 

 stature. The vessel was let down into a great depth, with 

 all the air it contained, in the same manner as was described 

 in the case of the platter, and was set upon its feet, and 

 stood just by the spot where the work was to be carried on, 

 But the divers, who were the workmen, when they wanted 

 respiration put their heads into the hollow of the vessel, 

 and having taken a supply of air, returned to their work. 

 And I myself in a bath made my servant put his head into 

 a basin under the water depressed with air, and he so re 

 mained for half the quarter of an hour, until he felt that 

 the air, warmed by his breath, brought on a feeling of suf 

 focation. 



To try by the bladder whether air readily admits of some 

 small contraction would be a fallacious experiment. For 

 when the bladder is filled with wind, the air is condensed 

 by the wind itself, so that the air within the bladder is more 

 dense than common air, and therefore may be expected to 

 be less adapted to a new condensation. But in the usual 

 experiment of the wooden plate forced down beneath the 

 water, you may see that the water, entering from the ex 

 treme part of the vessel, has occupied some space, and that 

 the air has occasioned a defalcation of the same space. 



But in order more clearly to illustrate the proportion, I 

 placed a small globular, or other solid body, and that would 

 sink, at the bottom of the vessel, above which the plate 



