Elastit FiiMff fo Bifilh'on, ^69 



The Doctor confesses his explanation of these 

 remarkable facts is very inadequate 5 aixl no 

 wonder, for it is impossible for him or any 

 other to explain them on the commonly received 

 principles of elastic fluids. But we will hear 

 what he says on the subject : — *' At present it 

 ^* is my opinion, that the agent in this case \n 

 ♦''that principle which we call attraction of 

 " cohesion, or that power by which wa^er is 

 " raised ift^ (papillary tube*^:- *' But in what 

 ^< manner it «k:t& ii^ this Case I am far from 

 *^ being able to explain. Much less can I 

 *' imagine how air should pass one way and 

 " vapour the other, in the same pores, and 

 " how the transmission of the one should be 

 ** necessary to the transmission of the other. — 

 ** lam satisfied, however, that it is by means 

 " of such pores as air may be forced through, 

 j^that this curious process is performed; be- 

 •* cause the experiment never succeeds but 

 " in such vessels as, by the air pump at least, 

 " appear to be porous, though in all such.** 



The truth is, these facts so difficult to ex- 

 plain are exactly similar to those which are the 

 subject of this Memoir: Only instead of a 

 great numher of pores we have one of sensible 

 magnitude, (the bore of the tube). Let the 

 porous retort have the same elastic fluid within 

 and without, in the one case ; and the two 



