TEMPERATURE AT FORT SULLY 1872 TO 1875. 
129 
So far as the annual and monthly means show, the year 1873 was 
about as favorable as to temperature as 1874 ; and as may be seen by 
reference to the table of rainfall (Table VII), it was equally favorable 
in this respect. As there was no marked or general invasion in 1871 or 
1872, it cannot be claimed that the permanent breeding grounds had 
been exhausted by migrations, as it is conceded that there was no general 
invasion in 1873, but was in 1874. Let us look to the daily records of 
the former and compare them with those of the latter year and see if 
they show any important differences. 
For this purpose we select Fort Sully as the station within the per- 
manent breeding grounds showing the most complete record. The fol- 
lowing table is the daily record of the maximum and minimum temper- 
ature from October, 1872, to June, 1875. 
9l 
