88 The Total Solar Eclipse of 1900. 
phase preceding totality, began at about 3" 1", or about 8™ after first contact. 
The minimum is not very well marked, or rather there are two minima, occurring 
at 4" 11™ and 4° 18", respectively, between which a slight rise of about three- 
fourths of a degree occurs. This rise is probably due to an air-current bringing 
some air, previously warmed up by the direct rays of the Sun, into the thermo- 
meter screen. For though it was not specially noted that any wind arose during 
totality, yet such a phenomenon is a usual accompaniment of the total phase of 
an eclipse. The mean of the two times, given above, is 4" 14-5", and, if we take 
this to be the time of the true minimum, we find it lagging behind the time. of 
mid-totality, which occurred at 4% 6:2”, by almost the same interval as the first 
falling off in temperature lagged behind the. beginning of the eclipse. 
The rate of increase of temperature after totality appears to have been very 
similar to that of the decrease in the earlier phase; but the observations were 
discontinued at 4" 41™, as it was found that the Sun’s direct rays were just 
beginning to reach the thermograph through an opening in the screen, which 
had been insufficiently closed. 
