FORMATION OF RAINDROPS AND HAILSTONES. 523 



so as to form still larger particles which will move with greater 

 velocity, and more quickly overtaking the particles in front of them 

 will add to their size at an increasing rate. 



Under such circumstances, therefore, the cloud would be converted 

 into rain or hail according as the particles were water or ice. 



The size of the drops from such a cloud would depend simply on 

 the quantity of water suspended in the space swept through by the 

 drop in its descent, that is to say, on the density and thickness of the 

 cloud below the point from which the drops started. 



The author's object is to suggest that this is the actual way in 

 which raindrops and hailstones are formed. He was first led to this 

 conclusion from observing closely the structure of ordinary hailstones. 

 Although to the casual observer hailstones may appear to have no 

 particular shape except that of more or less imperfect spheres, on 

 closer inspection they are seen all to partake more or less of a conical 



Pig. 2. Broken Hailstone. 



form with a rounded base like the sector of a sphere. In texture they 

 have the appearance of an aggregation of minute particles of ice fitting 

 closely together, but without any crystallization such as that seen in 

 the snow-flake, although the surface of the cone is striated, the strice 

 radiating from the vertex. Such a form and texture as this is exactly 

 what would result if the stones were formed in the manner described 

 above. When a particle which ultimately formed the vertex of the 

 cone started on its downward descent and encountered other particles 

 on its lower face, they would adhere to it, however slightly. The 

 mass, therefore, would grow in thickness downward ; and as some of 

 the particles would strike the face so close to the edge that they would 

 overhang, the lower face would continually grow broader, and a coni- 

 cal form be given to the mass above. 



When found on the ground the hailstones are generally imperfect; 

 and besides such bruises as may be accounted for by the fall, many 

 of them appear to have been imperfect before reaching the ground. 

 Such deformities, however, may be easily accounted for. The larger 

 stones fall faster than those which are smaller, and consequently may 



