586 C. MTCH1E SMITH ON 



Before discussing these it is necessary to note that when the observations 

 were not made at the "post " they were made at places where I found that in 

 tine weather I got readings very nearly the same as those got at the post. It 

 is not necessary to go over the whole table. A few of the more marked cases 

 will sufficiently illustrate the main features. 



No. at ll 1 ' 20 m the reading on the edge of a dissolving mist was 47, while 

 the average for that hour is about 87. 



No. 8 shows small quantities of mist passing and dissolving, and the 

 readings varying from 50 to 97. The normal reading for this time being 

 about 90. 



No. 9. This reading was taken at some distance from the post as the mist 

 was drifting up a ravine to the west, and I stood so as to be just in the mist. 

 The readings were very low — 46 to 27. 



No. 11, taken at the same place as No. 9, gave a reading of 22. The mist 

 was then thicker, and so went farther before it was completely dissipated, but 

 it was clearly a dissolving mist. 



No. 13 is a doubtful case, as the mist was all round, but as it cleared off' 

 soon after it was probably even then dissolving. 



Nos. 20 and 24 are very clear cases. 



No. 26. Here the readings are from 160 to 128 when the normal was about 

 93. This mist was a very wetting one. 



Nos. 27 and 28 are also far above the average. 



Nos. 31 to 38 were all in thick condensing mists, and in each case the 

 readings are far above the average. I may add that I purposely avoided 

 examining the observations in detail at the time, and simply recorded as many 

 as possible. It should be noted, too, that in heavy wet mists the readings may 

 at times be too low, as the ebonite which insulates the wire in communication 

 with the inside of the electrometer is apt to get moist in spite of the umbrella. 

 This difficulty is got over by using a match which burns quickly, and by seeing 

 that the ebonite is quite dry before each observation. With a slow burning 

 match I found the results quite untrustworthy. 



The observations detailed above are by no means conclusive evidence of the 

 theory that I have ventured to draw from them, but they are sufficient to show 

 the importance of a much more careful examination of the electrical state of 

 condensing and dissipating mists. Such observations would be of great value 

 in connection with the discussion of the cause of thunderstorms, and if my 

 results are confirmed by more extended observations strong support will be 

 given to the theory which looks on the condensation of a number of slightly 

 charged particles into large drops as the cause of the high potential indicated 

 by disruptive discharges. It has been suggested as an explanation of some o\ 

 my observations that every cloud is surrounded by a zone at a lower potential 



