VOL. XXVI.] PHILOSOPHICAL TRANSACTIONS. 46? 



ascend in it: it rose a pretty pace at first; for in l6 minutes time it had 

 ascended near an inch and three quarters: but as it rose higher, its progress 

 became slower; for at the end of 24 hours, the water had attained only to l6 

 inches; the bladder at the top being near half filled with that air which had 

 deserted the ashes as the water ascended in them. At the same time I found 

 the upper part of the tube, to which the bladder was tied, to be cracked round, 

 and soon after dropped off. However I had the satisfaction desired. And thus 

 continuing the experiment, I found at 24 hours from the last observation, that 

 the water had ascended in the ashes 6 inches higher, which was very discernible 

 by the change of colour it gave them, distinct from those that were dry. 



Again, at the like distance of time from the last notice, the water had risen 

 4 inches and a half, and something better. On the 4th day, at the usual time 

 of observation, it had ascended 3 inches higher: and when the following 24 

 hours were finished, the water reached within half an inch of the top, by its 

 ascent of 2 inches. About 10 hours after, it had completely reached the ex- 

 tremity of the tube. Then desiring to know what quantity of water the ashes 

 had absorbed, I weighed a glass of water nicely, part of which I poured into 

 the glass, in which the tube had all along been kept, till it reached the mark 

 where the surface of the water stood at, when the tube was first plunged into 

 it ; and found the quantity equal to the weight of 1792 grains, which is nearly 

 the bulk of 7 cubical inches ; the capacity of the whole tube, in which it rose, 

 being equal to only 13 inches of the same denomination. Now this experiment 

 to me seems surprising enough from the following observations. 



1st. That the water not only ascended in the ashes, as between the before- 

 mentioned planes, and in the small tubes, contrary to its natural gravitation ; but 

 with such a power too, as to force and drive away pretty strongly imprisoned 

 air, which was contained in the interstices of the rammed ashes. 2dly, That 

 the removal of this imprisoned air could not be done without a power sur- 

 mounting its resistance, which must be great, since upon endeavouring to force 

 air through the body of ashes by the strength of my breath, when the tube 

 was not above half filled, it proved unsuccessful. Not but that I believe, if 

 the same force had been continued for some time, it would have found its way 

 through. Sdly, That the water ascends fastest at first, when there is a larger 

 quantity of intersticial air to remove, than when the column of the dry ashes 

 becomes shorter, by the higher ascent of the water in them. 4thly, That 

 notwithstanding the tube was rammed as full as possible with ashes; yet their 

 interstices were so many, as to receive or imbibe another body equal in bulk 

 to above half the contents of the whole. Sthly, That the water rose, not 

 only in the ashes adjoining to the inner surface of the tube, but equally in the 



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