Appendix II. 

 METEOROLOGICAL OBSERVATIONS. 



BY 



HARRY FIELDING REID. 



A louvred box, open below, was mounted on posts about 6 feet above 

 the ground ; it was about 20 feet behind our tents. In it were placed the 

 wet and dry bulb, the maximum and minimum, and the self-recording 

 thermometers. To one of the supporting posts was fastened a long box 

 with a hinged door in which hung a mercurial barometer (lent by the 

 United States Coast and Geodetic Survey). The rain gauge (lent by the 

 United States Signal Service) was placed on the ground about 30 feet in 

 front of the tent. Readings of these instruments (except the maximum, 

 minimum, and self-recording thermometers) were made three times a 

 day, at 7 a. m., 2 p. m. and 9 p. m. These observations, though made by 

 all members of the party, were under the direct charge of Mr Gushing.* 



I append some meteorological data which may be interesting : The dif- 

 ference between the mean temperature at Muir inlet and at Juneau (the 

 latter averaged from 8 a. in. and 8 p. m. readings) will be at once noticed. 

 The observations from the latter place were sent me by the Signal Service. 



The dial of the self-recording thermometer showed rapid variations of 

 temperature, amounting sometimes to 5° E. in as many minutes. During 

 our stay at the glacier we had three or four strong southerly gales. The 

 thermometer rose 10° or 15° within an hour, held this high temperature 

 during the gale, which usually lasted six or eight hours, and fell even 

 more suddenly to its usual height. Our highest temperatures were re- 

 corded during these gales, even when they occurred at night. 



The 2 p. m. barometric mean does not show a depression. This, of 

 course, is partly due to the high latitude, but I do not think that is the 

 whole cause. The difference of temperature between the air over the 

 snow-fields and over the neighboring country is greatest in the early after- 

 noon, resulting in a maximum difference of pressure at that time. The 

 flag at our camp blew more strongly toward the south during the warm 

 part of the day than at other times. For several consecutive days in Sep- 

 tember it hung quietly all night. Thus the proximity of extensive snow- 

 fields holds the barometer up in the afternoon and interferes with the 

 usual minimum. We have, unfortunately, no observations at a near 

 station with which we can compare our own in order to deduce a quanti- 

 tative value of the glacier's influence on the barometer.- 



* A complete record of these observations has been sent to the United 

 States Signal Service. 



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