178 Mr. T. Tate on the Magnitude of a Drop of Liquid 



Here the near coincidence of the results in the second and 

 third columns shows that the weight of the drop is in propor- 

 tion to the diameter of the tube. 



When the diameter of the tube exceeds seven-tenths of an 

 inch, the continuity of the liquid seems to be broken by the 

 agitation occasioned by the falling of the drop, and then the 

 whole volume of the liquid in the tube falls, but not in the form 

 of a regular drop. 



The law just enunciated has a remarkable relation to that of 

 capillarity. Since the height to which water rises in a tube, by 

 the action of capillarity, varies inversely as the diameter of the 

 tube, it follows that the weight of water rising in any tube from 

 this cause varies directly as the diameter : hence the weight of 

 the drop is in proportion to the weight of water which would be 

 raised in that tube by capillary action. 



When the liquid drop is formed upon a flat circular surface, 

 the law expressing its weight assumes a more general form. In 

 this case it was found that the augmentations of weight were in 

 proportion to the diameters of the circular surfaces. In these 

 experiments, the surface on which the drop was formed was the 

 horizontal base of a solid cylinder of hard wood, the liquid 

 being conveyed by the calico strip uniformly over the exterior 

 surface. 



Table II. — Results of Experiment on the Weight of a drop of 

 Water, formed on circular surfaces of different diameters, at 

 constant temperature 50°. 



Diameter of surface, 



Corresponding weight 



Value of to by formula 



in inches, 

 D. 



of drop, in grains, 



iy=-22+27D. 



1 



•41 



•49 



•2 



76 



•76 



•3 



110 



103 



•4 



1-32 



1-30 



•5 



1-56 



1-57 



•6 



1-78 



1-84 



•7 



215 



211 



Here the near coincidence of the results in the second and 

 third columns shows that the formula w='22-\-2'7D very 

 nearly expresses the weights of the drops : from this formula it 

 follows that the augmentations of weight are in proportion to the 

 diameters of the surfaces on which the drops are formed. 



The drop given off from the circular surface whose diameter 

 is seven-tenths of an inch is the greatest that can beformed in 

 this manner, as will appear from the result of the following ex- 

 periment. 



A circular horizontal surface of indefinite diameter gave a*drop 



