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"5° 

 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 



Mean relative humidity, 8 — 9 a.m., 44*5 7„ 



noon ... 43 7, 

 5—6 p.m., 56 7„ 





5) 



!5 



23-2° F. 



53-8° 

 30-6° 



15-0; 



6l"2° 



38-5° 



Many observations 

 included which 

 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, 



2o"3°- 



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



fluctuated greatly in a short time. Thus, on Aug. 1 2 it was 46 7o at noon, 



and 79 7o at 2 p.m. 



Average Cloudiness (10 indicating a Sky completely Overcast) 



