42 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 65 



B. OBSERVATIONS ON THE SUMMITS OF MOUNT WHITNEY (4,420 M.), 



OF MOUNT SAN ANTONIO (3,000 M.), OF MOUNT SAN GORGONIO 



(3,500 M.), AND AT LONE PINE CANYON (2,500 M.). 



These observations will be discussed further on in connection with 

 the observations made simultaneously at lower altitudes. Here they 

 will be considered separately in regard to the conditions of tempera- 

 ture and humidity prevailing - at the high level stations. The problem 

 to be investigated is this: Is the effective radiation, or the radia- 

 tion of the atmosphere, at the high stations in any way different 

 from the radiation found at lower altitudes, under the same condi- 

 tions of temperature and humidity? Or is the average radiation of 

 the atmosphere, at the altitudes here considered, a constant function 

 of the temperature and the humidity? Will there not be other 

 variables introduced when we move from one place to another at 

 different altitudes ? In the theoretical part I have pointed out some 

 facts that ought to be considered in this connection and I then arrived 

 at the conclusion that the effect on the radiation of temperature and 

 humidity ought to prevail over other influences in the lower layers 

 of the atmosphere. 



The observations are given in tables 16 to 19. The tables also give 

 the radiation of the atmosphere corresponding to each individual 

 observation, as well as this radiation reduced to a temperature of 

 20 C. by means of the relation : 



E«L-(I\ a 

 E at -\Tj 



where a is assumed to have the same value as that obtained from our 

 observations at Indio and at Lone Pine. The observations given 

 in tables 16 to 19 are now arranged in tables V and VI in a way 

 exactly similar to that which I have employed for the Algerian obser- 

 vations, except that in tables- V and VI, I deal with the radiation. of 

 the atmosphere toward the instrument, instead of the reverse, as in 

 table II. The relation of the two functions has been explained above. 

 From the tables it is seen that the Mount Whitney values, reduced 

 in the way described, seem to fall to values a little lower than what 

 would correspond to the form of the Algerian curve, as given above 

 by the formula E a =0.453 — °- I 34 " <?"°' 10p . The reason for this 

 discrepancy may be partly that the exponent a is not quite the same 

 for thin as for thick radiating layers. This explanation is rendered 

 unlikely by the calculations of Bigelow and the observations of Very 

 and Paschen on radiating layers of moist air. But there are other 



