RAIN AND ITS ORIGIN IN THUNDERSTORMS. 

 TABLE XIV. 



401 



As all the drops in these experiments contained approximately 0"24 c.c. of water, 

 the charge given to the water is equivalent to a volume charge of 23X10" 3 electro- 

 static unit per cubic centimetre of water. 



After making these experiments it was felt that objection might be raised to 

 applying the results thus obtained to the breaking up of raindrops in the atmosphere, 

 because no such violent scattering of the drops could take place in the atmosphere 

 as that obtained when falling drops impinge on a concentrated jet of air. A further 

 experiment was therefore devised to produce the breaking up of the drops in a more 

 natural way than the one already described. 



The apparatus used is sketched in fig. 3. BB was a vessel made out of tinned 

 iron, 65 cm. in diameter and 45 cm. high. In the middle of the bottom was a hole 

 7 cm. in diameter, surrounded by a conical rim 7 cm. deep ; thus a layer of water 

 7 cm. deep could be put into the vessel without running out through the hole. 

 Through this rim passed two small tubes, 0'8 cm. in diameter, which were fitted 

 with a simple arrangement for opening and closing them to allow of the passage of 

 the water at will. Soldered underneath the main vessel was a smaller one of the 

 shape shown in the figure, and around the upper rim a third vessel AA was fixed on 

 insulators so that it could be either connected to or insulated from the main vessel B, 

 according to the experiment to be made. The whole was supported on insulators in 

 such a position that the hole in the centre was directly over but not touching a 

 large pipe through which a blast of air could be sent by means of the rotatory fan F. 



When the fan was in action and the tubes open, water passed out through the 

 latter in a solid stream into the middle of the air current, by which it was at once 

 carried upwards and broken into spray. As the greater part of water carried 

 upwards fell back into the main reservoir of water, it could be used over and over 

 again. With this arrangement quite large charges were obtained by the vessel B in 

 a comparatively short time. For example, the vessel B was connected to A and the 

 water allowed to run. The whole system was then found to become charged at the 



VOL. ccux. A. 3 F 



