210 



A NATURALIST IN THE PACIFIC 



CHAP. 



lofty mountains 10,000 to 14,000 feet above the sea, we have a mean 

 temperature only found far north. Snow lies often on these barren 

 summits in winter, more particularly on Mauna Kea, which thus 

 derives its native name of the White Mountain. The details of 

 my meteorological observations on Mauna Loa will be found in 

 Note 61 ; and only some of the general results will be referred to 

 here. 



The mean temperature for the period of twenty-three days 

 passed by me on the summit of Mauna Loa (13,600 feet) between 

 August 9th and 31st, 1897, was 38-5° F. The mean temperature 

 for a period of twenty days from December 24th, 1 840, to January 

 1 2th, 1 841, during which Commodore Wilkes and his party were 

 making pendulum observations on the summit of the same moun- 

 tain, was approximately 33'5° (see Note 61). From these 

 results, which are tabulated below, it will be seen that the mean 

 annual temperature would be probably about 36", which is scarcely 

 comparable with any continental climate, since only a difference of 

 a few degrees is indicated between the mean temperatures of 

 August and of a similar period in mid-winter. I may add that 

 although it was in the summer month of August, water froze inside 

 my tent during twenty out of the twenty-three nights passed on 

 the top. We may, therefore, infer that the temperature falls below 

 the freezing point at night practically throughout the year. It will 

 be seen from the table that the mean annual temperature for the 

 summit of Mauna Loa, as here computed from the observations 

 of Commodore Wilkes and myself, comes very near to that which 

 might be estimated by employing Hann's tables of variation in 

 temperature with altitude on tropical mountains (see Schimper's 

 Plant- Geogyaphy, iv. 691). 



Winter and Summer Temperatures on the Summit of Mauna Loa 

 (13,600 feet), in Degrees Fahrenheit. 



Estimated mean annual temperature of the summit of Mauna 

 Loa, taking that of the coast at 75^ would be 34" if the rate of 

 increase was the same as on Mount Pangerango in Java (i"" per 

 328 feet). 



