1864.1 



Prof. Guthrie on Drops. 



463 



sphere) tangent to the sphere, laterally by a cylinder of vertical axis stand- 

 ing on the tangent plane and cutting the sphere, and above by the convex 

 surface of the sphere itself (Plate IV. fig. 4). 



As the diameter of the sphere still further diminishes, the size of the 

 drop is limited by the possible size of its base, until finally the sphere is 

 completely included in the drop. 



It would be interesting, but it would take us too far, to consider the vari- 

 ous cases of liquids dropping from cones, edges, solid angles, cylinders, 

 rings, &c. We must content ourselves in this direction with the fact that 

 the size of a drop is greater the more nearly plane is the surface from 

 which the dropping takes place. If it were possible for a drop to fall from 

 a concave surface, we should anticipate a still further increase in its size. 



The relation between drop-size and curvature may be more strikingly 

 shown by arranging the spheres one above the other in the order of mag- 

 nitude. 



Plate IV. fig. 5. — Each sphere receives the drops from the higher one. 

 The quantity of water which drops in a given time, from every sphere, is the 

 same. Hence in all cases the number of drops is inversely as the drop- 



Table l^.^Water. 

 T=23°C. 



1. 





2. 



3. 





4. 



Radius 

 of disk. 



Number 

 of drops. 



Weight 

 of drops. 



Mean weight 

 and relative size 

 of single drop. 



in. 



5 



20 



4 

 20 



3 

 20 



2 

 20 



1 



20 



1 

 1 



^20 

 20 

 20 

 20 

 1 20 

 '20 

 20 

 20 

 .20 

 '20 

 20 

 20 

 .20 

 [20 

 20 

 20 

 l20 

 ^20 

 20 

 20 

 ,20 



gTm. 

 3-3682 \ 

 3-1193 

 3-2523 

 3-3256 

 3-2594 ; 

 2-9693"^ 

 2-9854 



2- 9746 



3- 0031 

 1-9333' 

 1-9244 

 1-9504 

 1-9248 

 1-4618' 

 1-4672 

 1-4688 

 1-4682 

 0-82501 

 0-8212 

 0-8208 

 0-8190 



1 

 1 



0-16325 



0-14915 

 0-09666 

 0-07332 

 0-04107 



size ; so that by counting the number of drops which fall from any two 

 spheres in the same time, we get at once the relative sizes of the respective 



