E. Loomis on Solar Spots, Magnetic Declination, etc. 171 
1. Those cases in which the observers were not entirely con- 
—— that there was any auroral display. 
Those cases in which the oa observations of 
Pe solar spots were very incomplet d 
ose cases in which auroras were observed on two or 
three successive days, when I have generally selected the most 
remarkable aurora, and made but one entry for that period. 
The number of auroras which I have thus discussed is 251. 
In order to furnish a specimen of these numbers, the table on 
page 170 is given, in which the arrangement is the same as in 
the table on page 168. At the bottom of the table are given 
the averages of these numbers for each of the 13 columns; and 
in another line are given = corresponding averages for the 
whole number of 251 auro 
These final averages are represented by the upper curve line 
in the figure page 169, from which it will be seen that there is 
a well-marked maximum of solar Ftc adian corresponding to 
the date of an auroral display. The small fluctuations during 
the preceding and following days, bear some resemblance to the 
fluctuations attending magnetic storms, but they are so small in 
amount that no importance is attached to them. The entire 
fluctuation within 6 days extends from 503 to 60°5, or 20 per 
cent of the whole quantity; a number so large and derived 
from so many cases that it is ao to indicate a law of na- 
ture. Hence we conclude t 
te 
observations which furnish for each day an exact measurement 
of the extent of the sun’s spotted surface. Such observations 
e 
vi} 7 Bppeere: * | 
for 1869, pp. pila and it is expected that the observations 
ty 
