TAKES PLACE BETWEEN BODIES OF DIFFERENT FORMS. 39 



action of capillary systems. It is an electrical force that determines all kinds of con- 

 stitutional changes developed in bodies by the chemistry of organic life, and it is a 

 manifestation of the very same force that carries some fluids along the almost invisible 

 vessels of living structures, and denies to others a passage. All the phenomena of inor- 

 ganic chemistry are the result of the balancings of the force of cohesion on the one 

 hand, and electrical attraction on the other. If Berthollet was wrong in supposing 

 that chemical affinity, as an acting force, had no existence, other chemists have equally 

 erred in supposing that all kinds of changes, without any limitation, were due to 

 it. Whether we investigate the phenomena of chemistry or of capillarity, we have 

 the same forces to deal with, acting as antagonists to each other ; and hence the whole 

 effects imputed to capillary attraction may be regarded as belonging to that extensive 

 class which the science of chemistry considers. 



125. There is a variety of facts recorded by writers on capillary attraction, which an 

 application of these principles readily explains, though hitherto they have been regarded 

 by philosophers as remarkable anomalies. Such is the observation of HUYGENS, that 

 it was possible to cause mercury to stand in a barometer seventy inches high ; or that 

 of P. Abat, of a singular deviation in the hydrostatic level of the same fluid in different 

 branches of a siphon. 



126. Capillary attraction does not take place only between solids and fluids ; it is 

 exhibited when solids alone are made use of. In virtue of this power, two pieces of 

 lead cohere with great energy to each other, as also is the case with two planes of pol- 

 ished stone or plates of glass. When glass is used, electricity of very high tension is 

 readily detected, one of the pieces being positive and the other negative ; it would, I 

 suppose, hardly be denied that the force operating in the case of glass is also the force 

 that operates in the case of stones. Is it not, then, a legitimate supposition, that the 

 adhesion of two pieces of lead is brought about by the same agent, the presence of 

 which is masked by the high conducting power of the metal 1 



127. Between solids and gases capillary action likewise takes place. On the sur- 

 face of all kinds of solids atmospheric air remains in a state of condensation, as is made 

 evident when such bodies are placed beneath water under an exhausted receiver ; the 

 air appearing in copious bubbles, studding the surface of the metal. 



128. Now having a power the operation of which over inorganic masses is so exten- 

 sive, it is for us to inquire how far the phenomena of organic systems depend upon 

 its working. Those numerous pores, and pipes, and capillary vessels which abound in 

 all kinds of living structures, but of the action of which we are so ignorant, point out to us 

 capillary attraction as one of the great forces in play, determining all kinds of motions 

 and physical changes. To identify the force producing motion of a mechanical char- 

 acter with that effecting physical change, gives a unity to the action of powers which 

 have hitherto been multiplied without avail, and stamps simplicity and symmetry on 

 actions that are very diverse. 



129. It is not alone in the vital functions that we meet with applications of the prin- 

 ciples of capillary action ; the mechanical functions furnish numerous instances. The . 

 organs of progression of some animals which delight to walk upon water are provided 



