LECT. II. LAWS OF CAPILLARITY. 31 



liquid rises and adheres to the glass or moistens it ; on the 

 contrary, it falls in the tube, if the liquid be not able to 

 moisten it. 



In a tube of 1 millimetre [about ^V f an English inch] 

 in diameter, the water rises 30 millimetres [about 1| English 

 inches;] and mercury falls 13 millimetres [about J an Eng- 

 lish inch.] It will be readily admitted that capillary actions 

 must exercise great influence over the functions of the tissues 

 of animals and vegetables, when we reflect that the inter- 

 stices and the capillary tubes of the tissues have a diameter 

 of from T ^ to jfo of a millimetre [about the ^^ to about 

 sffVir of an English inch.] 



4thly. The concave surface of the elevated liquid, and 

 the convexity of the depressed liquid, belong to a hemis- 

 phere whose diameter is equal to that of the tube. 



5thly. If a drop of water be introduced into a conical 

 glass tube [held in a horizontal position] it will run to the 

 narrower end; but if a drop of mercury be introduced, it 

 will, on the contrary, run to the wider end. 



6thly. The phenomena in question are entirely indepen- 

 dent of the volume of the solid body plunged into the liquid, 

 and consequently the thickness of the sides of the capillary 

 tube, in which they are observed, is without influence on 

 them. 



Tthly. These phenomena occur equally in air at the ordi- 

 nary pressure, in condensed or rarified air, in a vacuum, 

 and in any gaseous medium. 



Sthly. All bodies, of whatever nature, yield, if susceptible 

 of being moistened, the same results, provided that before 

 immersing them in the liquid we make a layer of it adhere 

 to them. 



9thly. For the same liquid, and with the same tube, the 

 elevation or depression of the interior liquid column is in 

 proportion to the temperature of the liquid, and in a greater 



