12 E. Loomis— Observations of the U. 8. Signal Service. 
a difference of 162°. The average difference of tempera- 
ture of these stations, as determined from six years’ observa- 
tions, is 19:0°. I next selected all the cases in which the 
thermometer at Portland, Me., during a period of five years 
sunk as low as +10°, and determined the lowest temperature 
on Mt. Washington for the same dates. The number of these 
cases was111. The average of these observations at Portland 
was +3:2°, and at Mt. Washington was —19-7°, showing a 
difference of 229°. The average difference of temperature of 
these stations for a period of six years has been 19°7°. If 
take the average of the results for Burlington and Portland, 
we shall find that during these cold periods the difference of 
temperature between Mt. Washington and the level of the sea 
was identically the same as shown by the daily observations 
of six years, 
ture at that station for the winter months, and may reasonably 
be ascribed to the heat developed during the winter months by 
the condensation of vapor on the Sierra Nevadas and the 
including the changes above mentioned. I have also added a 
second table showing the relative humidity for the same sta- 
tions at the same dates. 
