250 



M. Quetelet on Atmospheric Electricity, 



If Munich and Brussels were in tlie same electric condition^ 

 the numbers a and /3' would be equal, or at least would present 

 the same fluctuations. Thus, similar to all physicists who have 

 examined atmospheric electricity, we find that the electric tension 

 is stronger in winter than in summer ; but the ratio which you 

 obtain is hardly that of 2 to 1, while for Brussels it is about 

 9 to 1 . Is this enormous difference due to local causes ? I hardly 

 believe it. As you have not published, up to the present time, 

 the summary of your observations, and have not entered into 

 details with regard to the manner according to which your means 

 were calculated, I am not aware if all the observations without 

 distinction have been brought into the calculation or not. 



In this state of doubt I was desirous to compare our results 

 with others obtained in different localities; unhappily, however, 

 I know but one single series of observations on this interesting 

 but neglected portion of meteorology ; these are the observations 

 made at Kew by Mr. Ronalds from 1845 to 1847*. I give them 

 in the following table with the general results of Bnissels, for the 

 seven years from 1845 to 1851. The observations at Munich, 

 Brussels and Kew, have reference to the hour of noon; they 

 have been rendered comparable in three special columns by 

 taking for unity the monthly mean. 



* Report of the lf)th Mnctiug of the British Association held at Bir- 

 mingham in September 184!> ; see the memoir of Mr. Birt, p. 113. 



