480 PHILOSOPHICAL TRANSACTIONS. [aNNO I67O, 



endeavoured to make this loss visible by some other trials, of which I can find 

 but a few hasty memorials among my loose entries. 



A chemical pipe, sealed at one end, about 36 inches in length, was filled 

 with water, and inverted into a glass vessel, not two inches in diameter, and 

 but -L of an inch or little more in depth. These glasses being conveyed into a 

 fit receiver, and the air being leisurely pumped out, and somewhat slowly re- 

 admitted, the numerous bubbles, that had ascended during the operation, con- 

 stituted at the top an aerial aggregate, mounting to -pV wanting about 100th 

 part of an inch. 



Presently after, the tube (hereafter to be described) was filled again with the 

 same water, and inverted, and the water being drawn down to the surface of 

 the vesseled water, and the air let in again, the water was impelled up to the 

 very top within a tenth and half a tenth of an inch. 



The tube for measuring the air latent in water was 4 3 J- inches above the sur 

 face of the stagnant water : the air collected out of the bubbles at the top of the 

 water, was the first time 4- of an inch, and somewhat better ; the second time 

 we estimated it but -i- and -^V- The first time the water in the pipe was made 

 to subside full as low as the surface of the restagnant water : the second time 

 the lowest that we made it subside, seemed to be four or five inches above the 

 surface of the water in the open vessel. 



Matter of fact thus recited would afford several difficulties worthy to be con- 

 sidered, which I have not leisure to discuss; especially the odd thing that hap- 

 pens to the aerial particles of water : For though, whilst they lay concealed in 

 the water, they took up so little room in it, that it was insensible, and when 

 they were permitted to escape out of the tube, the water was not manifestly 

 diminished by their recess; yet when they were associated at the top of the tube, 

 their aggregate did sometimes maintain a place, that was considerable enough in 

 reference to the capacity of the whole tube ; though I must here notice, that 

 this aggregate did at the top of the tube possess more room than its bulk abso- 

 lutely required, because it was somewhat defended from the pressure of the at- 

 mosphere by the weight of the subjacent cylinder of water, which might be 

 about three or four feet long. 



Query. Whether any considerable proportion of bubbles will be afforded by 

 the same liquor, if it be suffered to continue in the glass for some competent 

 time, after it has been once or oftener freed from bubbles already? 



Query. How far it may be worthy our consideration, whether in common 

 water there may not be concealed air enough to be of use to such cold animals 

 as fishes; and whether it may be separable from the water that strains through 

 tiieir gills? 



