APPENDIX 



591 



Method of Observation employed by the Author on the Summit of Mauna 

 Loa. — My camp was placed near the middle of the west margin of 

 the crater about 13,500 feet above the sea. The instruments employed 

 were a Sixe's maximum and minimum thermometer made by Negretti and 

 Zambra, several unmounted thermometers, and a reference thermometer 

 (with a Kew certificate) by the above-named makers, which was used as a 

 standard. The freezing point was also tested for all the instruments on the 

 summit in melting powdered ice. The maximum air observations and 

 those on the relative humidity were taken in a small cave with a hole 

 in the roof, through which there was a steady flow of air. One day 

 was occupied in comparing the cave-observations with those obtained 

 under a temporary screen rigged up outside my tent, the only difference 

 shown being as a rule less than a degree. The minimum observations 

 taken in my tent, where there was no artificial heat, were usually only I'S" 

 higher than those given by a thermometer outside the tent. 



Results of the Observations on the Top of Mauna Loa, Aug. 9-31, 1897 



Mean minimum temperature of air in shade 

 Mean maximum „ „ ,, 

 Mean daily range of temperature 



Lowest reading 



Highest reading 



Mean temperature for the period 



23-2° F. 



53-8° 



30-6° 



6l"2° 



38-5° 



, . , -J., o ., '] \ Many observations 



Mean relative humidity, 8-9 a.m., 44 5 I. \ included which 

 noon ... 43 /o " ■ ' ' 



5— 6 p.m., 56 % 



C are not given in 



the register. 



On Aug. nth, at 10 a.m., wet bulb, 33-2° ; dry bulb, 52° ; difference, 



i8-8°. 



On Aug. 19th, at 11 a.m., wet bulb, 357°; dry bulb, 56 ; difference, 



. o 

 20 3 . 



Owing to the varying winds at my camp, the relative humidity 

 fluctuated greatly in a short time. Thus, on Aug. 12 it was 46 7„ at noon, 

 and 79 7o at 2 p.m. 



Average Cloudiness (10 



12 — 4 A.M. 



4-8 » 

 8—12 „ 



12 4 P.M. 



4 — 8 „ 

 8 — 12 „ 



o 



o 



I '3 



3-5 



1-5 



o 



indicating a Sky completely Overcast) 

 Cloudless during 12 out of 13 days 



