﻿380 



M. G. Quincke on the Capillary Phenomena 



The mean value of the numbers of the fifth column agrees very 

 nearly with the constant a 12 = 4*256 milligrammes, derived from 

 observation of the drops (compare Table X. § 10) . Thus the 

 angle g> 12 in the experiments on capillary tubes was nearly 180°, 

 whilst according to the earlier method, from observation of drops 

 on a glass plane, it was found to be 167°. 



These experiments, as well as those of the foregoing para- 

 graph, may be looked upon as a confirmation of the theoretical 

 considerations. 



18. If we observe the elevation in vertical capillary tubes, 

 whose upper end opens into olive-oily and lower end into water, 

 then a depression or an elevation of the capillary meniscus below 

 or above the common plane limiting surface of the two liquids 

 will take place, according to whether the capillary tube before the 

 submersion was filled with olive-oil or water, and consequently 

 according to whether the sides of the tube were moistened with 

 olive-oil or water. This circumstance appears to me worthy of 

 notice, as it shows with what difficulty an adsorbed layer of 

 liquid is expelled from a solid body. Water which only now 

 comes into contact with the solid sides behaves quite differently 

 from water which is already in contact with them; it is the 

 same with regard to olive-oil. 



Table XVI. — Elevation in submerged capillary Tubes. 

 Water — Olive-oil . 



No. 



2r. 



h. 



hr. 



a 12 COS w 12 . 



"12" 



1. 

 2. 



milliras. 

 2-612 

 2-304 



millims. 

 -18 

 341 



sq. millims. 

 -23-51 

 39-29 



mgrm. 



-1015 



1-697 



118 58 

 35 57 



The last column of the above Table contains the values of the 

 angle <o iq , calculated on the assumption that a 12 = 2*096 milli- 

 grammes, as was found from observation of the drops. 



With drops of olive-oil, which were placed under a glass plane 

 moistened with water, I found the angle &> ]2 = 17° (§ 10), a value 

 which, considering the uncertainty of the method used, does not 

 strikingly differ from 35° 57 l ,fo\m& in the present analogous case. 



IV. Elevations in capillary tubes of several liquids superposed. 



19. A fourth method of observing capillary phenomena at the 

 common limit of two liquids consists in placing on a liquid u in 

 a capillary tube a second liquid o, and observing the common 

 elevation of the two liquids. 



This method, as has been already mentioned (§ 2), was used 

 by Th. Young, Gay-Lussac, and Bede. 



