en an Se eae y ae ee eee 
J. Brocklesby— Rainfall in the United States, ete. 489 
aging ;1, second up to about the 10th flash ; after this the in- 
tervals of the flashes rapidly close up, so that during the fourth 
fifth of the discharge they follow at each ;;';5 of a second. 
During the last fifth of the discharge the intervals between the 
flashes gradually increase, and the last flash is separated from 
its predecessor by ,,'5, of a second. 
Discharge of large inductorium between brass balls; one em. in 
diameter, separated one mm., with a Leyden jar of 242 sq. cm. 
mner coating, connected with the terminals of the secondary coil. 
This discharge also lasts ;'; second, and is similar to the pre- 
ceding, except that larger circles are made on the dise by the 
dissipation of the carbon, and that there are fewer flashes, viz., 
71. The total number of spark-holes in these flashes is 123. 
Thus, there are fewer flashes than in the experiments with the 
platinum points, but the total number of spark-holes is the 
same in each case. Hence there is, on an average, 1°34 spark to 
each flash with the points, and 1°78 spark-holes. to each flash 
with the balls. 
xperiments have also been made with rotating discs formed 
of “sensitized ” paper, and interesting results have been ob- 
tained. 
October 15, 1874. 
Art. XLI.— On the Periodicity of the Rainfull in the United 
States in relation to the Periodicity of the Solar Spots; by Pro- 
fessor JOHN BrocKLesBy, of Trinity College, Hartford, Ct. 
THE researches of scientists, especially of late, lead to the 
Conclusion that there is an intimate connection, more or less 
Meteorological Observatory at Mauritius, and it is claimed by 
Mr. Meldrum and others that the variation in the annual rain- 
cOmmotions. 
