and its relation to Latent Heat. ^ 



capillary force in small tubes. I found that so small a propor- 

 tion as 12 per cent, of alcohol destroyed the abnormal tendency 

 of water. I made no observations with tubes of from ^'jth to 

 Ji^th of an inch diameter ; but in tubes of j^^th of an inch and 

 larger, the abnormal feature was found not to exist (see § 3). I 

 found also that in all tubes that do not touch a water surface, 

 but that receive their supply of water at the lower rim by capil- 

 lary pipette, as in the observations described in § 2, when the 

 upper surface is at its maximum elevation, the interior capillary 

 volume estimated above the lower rim has the abnormal ratio 

 to the internal water-line. When the tubes thus filled to the 

 capillary maximum are brought to touch a water surface, the 

 water in the wider tubes descends to the normal level, but in the 

 finer tubes it does not. With alcohol and its class, in fine tubes 

 thus supplied at their lower extremities, the maximum abnormal 

 level is never attained, but in the wider tubes the phsenomena 

 occur precisely as with hydrous hquids. 



§ 9. To find the capillarity of alcohol, I tried spirits of various 

 strengths in a thermometer-tube ; and by setting off the heights 

 of the capillary column and the specific gravities as coordinates, 

 and drawing the curve, it was easy to obtain the height corre- 

 sponding to 0-783, the specific gravity of absolute alcohol at the 

 temperature 86° F., according to Lowitz's Table. This, com- 

 pared with the height of the water-column in the same tube, 

 gave 228 as the value of Q for absolute alcohol, after making 

 the reduction required by the abnormal height of water in fine 

 tubes. The value of the ratio of reduction is mainly dependent 

 on comparative plate-observations, which are not so precise as 

 comparative tube-observations; but it is satisfactory that it 

 agrees closely with the recent observations of M. G. Wertheim, 

 noticed in the Philosophical RIagazine for October last. 



The following are the values of Q for sulphuric aether and 

 some other liquids taken at 80° V. : — • 

 228. Absolute alcohol. 

 3G1. Sulphuric a;ther (of commerce). 

 199. Camphcnc. (212) 

 355. Chloroform. 

 225. Acetic acid. 



202. Acetic ajthcr. 

 225. Acetone. 



288. Snlphuret of carbon. 

 257. Cliloride of sulpliur. 



143. Ammonia. 



203. Sulphuric acid. 

 270. Nitric acid. 

 133. Distilled water. 



