+ j ROYAL SOCIETY OF CANADA 
tc the temperature changes, “ the earlier change at the summit in both 
cold waves and hot waves is remarkable, and does not seem to be due, 
as has been suggested, to the great rapidity of the upper current which 
carries the warm or cold air from the west more rapidly to the summit 
than to the base. It will be seen that any effect of this kind would 
be quickly obliterated by the motion of the air.” 
While clearly recognizing the advance changes which are indicated 
at the higher level, Professor Hazen does not regard them as being 
due to great convection currents carrying the warmer or cooler air. He 
considers that a general mixing would result, thus obliterating any 
sharp line of temperature difference that might exist. From what we 
know, however, of the persistence of stream-line motions in fluids, and 
of the great influence which temperature seems to have in preserving 
a line of separation between heated and cooled masses, it seems to us 
that great convection streams might be easily obtained in the upper 
atmosphere, and be a considerable time in affecting the temperature of 
the air in closer proximity of the earth. Our observations seem to 
indicate that the large temperature changes which occur at Montreal 
are due to advance streams of colder or warmer air travelling through 
the atmosphere above the earth and affecting the lower layers only after 
a considerable lapse of time. It is very much to be desired that observa- 
tions be made of the temperature at an elevation much higher than our 
present high level instrument, but it does not seem possible for us at 
present to carry out such a plan. 
In regard to the temperature effects at very high altitudes of land, 
an exceedingly interesting account has recently been given of the Mount 
Rose Weather Observatory by Professor J. E. Church, Jr! Mount 
Rose is south of Reno, Nevada, and north, northeast of Lake Tahoe, 
and forms the northern apex of the Carson Range of the Sierra Nevada; 
it has an altitude of 10,800 feet. Its value as a site for a mountain 
weather observatory lies in the fact that the mountain is so surrounded 
by the depressions of the Lake Tahoe and Truckee River basins that 
its summit furnishes an ideal site for observing the condition of the 
weather in mid-air. As Prof. Church also points out, it rises in the 
agricultural zone on the height of land between the California basin 
the Nevada-Utah plateau, so that an observatory there would be of 
service in furnishing data as to the constant air movements from the 
Pacific coast, and in reporting approaching weather conditions to the 
districts farther east. It is conveniently situated near Reno, and the 
summit is within reach in winter as well as summer. As regards being 
an isolated land mass Mount Rose resembles our more modest Mount 


Monthly Weather Review, Vol. 34, p. 255 (1906). 
