296 



WRITINGS OF JOSEPH HENRY. 



[1855- 



FiG. 10. 



and the shaded portion above exhibits the cloud formed by 

 the condensed vapor which is thrown outward on each side. 

 The rain falling in the axis of the uprising column by its 

 weight forces out the air in the direction of the arrows at 

 the foot of the column. 



When the air is saturated with moisture in warm weather, 

 and especially when the sensation called closeness is observed, 

 the rushing up of the column through a confined space ma}'' 

 be so violent that drops of water may be carried up beyond 

 the point of congelation and be converted into ice, and these 

 will be thrown out on each side, exhibiting the phenomenon 

 often observed in storms of this character, of two streaks of 

 hail along the course of the tornado. In some cases these 

 pieces of frozen water will be caught up by the inblowing 

 air below and carried up again, perhaps several times in 

 succession, each time receiving new accretions, and thus 

 large hail stones will be formed exhibiting a concentric 

 structure in which the centre will be of a light spongy con- 

 sistency, and this succeeded by a stratum of transparent ice 

 and this again by another stratum of snowy appearance, and 

 so on, the outer surface being covered with large projecting 

 crystals of solid ice. These facts are in strict accordance 

 with what we might have predicted from the theory we have 



