McClelland and Nolan — 'the Electric Charge m Rain. 69 



The results were as follows : — 



{1) First Shower. — The flakes were very small. Fifty-five grammes of snow 

 had a charge of 553 negative electrostatic units. The potential had 

 a very high negative A'alue during the shower. 



(2) Second SJioirer. — The flakes were at first small, ami 30 grammes 

 collected during the period liad a charge of 176 negative units. 

 Later the flakes were large, and 245 grammes gave a charge of 

 830 positive units. The potential at first had a high negative value, 

 but after the sign of the charge on the snow had changed it took 

 a high positive value. 



{3.) Third S/ioiccr. — Little snow fell, and the flakes were very small. 

 Thirty grammes gave a charge of 7 negative units. The potential 

 was small. 



{4.) Fourth Shower. — The flakes were again small. A charge of 40 negative 

 luiits was given by 120 grammes of snow. The potential was small 

 during the fall of the snow ; just previously it fliietuated between 

 high positive and high negative values. 



The first three showers occurred in rapid succession, while the fom'th 

 was some hours later. The most remarkable feature of these few observations 

 Kjn snow is the high value of the charge per gramme both when positive and 

 when negative, and the very high values of the potential gradient during 

 the fall of the snow. Diuing the observations recorded in the previous 

 paper, we observed negative values of the potential during snow, as high 

 as 2500 volts, at a point where the normal potential was about 100 volts. 

 The high values now recorded were of a similar magnitude. 



The previous observations on a few snow-showers gave in each case a 

 negative charge ; from the present observations it wonid seem that the 

 larger flakes are positively charged. Simpson usually found a positive 

 ■charge on snow, and the diflerence may arise from the type dealt with. 



Only two very short showers of hail were observed ; and, as in the case of 

 a single shower pre\'iously recorded, the charge was positive and of the order 

 ^jf from one to two electrostatic units per gramme. 



In the case of one of these showers, it began as hail, then gradually 

 -changed to rain, l^o discontinuity in the electrical effects was noted, the 

 rain being of the highly charged positive type. This fact is interesting, 

 as it puts hail and higldy charged rain in the same category ; the circum- 

 stances of their occurrence are very similar, and in this case identical. 



R.I. A. PROC, VOL. XXX., SECT. A. [H] 



