GENERAL MEETING. 11 
increase during the time of new moon, thus corroborating the result 
previously obtained by Dr. Képpen. 
A comparison of storm frequency with the period of solar rotation 
gave a marked maximum during the rotation. It was shown that 
taking the mean temperature over the whole storm region there was 
a close relation between the occurrence of high temperature and 
storm action, the former preceding the latter by about 24 hours. 
Taking the mean of the meteorological elements on 20 days of 
many storms at many of the stations, it was found that a marked 
low-pressure area was present to the northwest of the storm region, 
there was also a high temperature, while the humidity and weather 
were normal. On 20 days of few storms the reverse was found true, 
namely, a relatively high pressure and low temperature, the humid- 
ity and weather being normal as before. These results were highly 
interesting as bearing upon the conditions favorable to thunderstorm 
action. The detailed study gives promise of large additions to our 
knowledge of these meteors. 
In the ensuing discussing, Messrs. Mussry, Ray, ANTISELL, E. 
Farquuar, Pau, GILBERT, Roprnson, and Hazen spoke of the 
topographic, geographic, and seasonal distribution of thunderstorms 
and of the relation of the precipitation to the electric phenomena. 
Mr. ANTISELL said that moisture is essential to their generation; 
they are a secondary effect of the influence of the sun, not a pri- 
mary. Mr. KE. FarquHar spoke of the concentration of electricity 
by diminution of aqueous surface, when cloud-particles coalesce and 
form raindrops. 
Mr. 8. M. Burnert exhibited and explained 
THE JAVAL AND SCHIOTZ OPHTHALMOMETER. 
Mr. A. B. Jonnson began a communication on 
THE DIFFICULTY IN DETERMINING THE DIRECTION OF SOUND. 
267TH MEETING. Marca 28, 1885. 
The President in the Chair. 
Forty-two members and guests present. 
The Chair announced the election to membership of Messrs. 
GusTAVE Louis Ravenk&, THomas MAREAN CHATARD, HERBERT 
