INTRODUCTION. XXvii 



equal. In fine weather, copious dews fall. The climate of Tutuillu 

 is much modified by the overhanging clouds, which shield the harbour 

 and its valleys from the powerful rays of the sun. The trade wind 

 sets in about ten o'clock and continues till sunset. The nights are 

 calm ; at times a faint land-breeze is felt. 



The rain which fell in eleven days of our stay at Pago Pago 

 harbour amounted to 4-3 inches; the degree of moisture in clear 

 weather '871. The climate of the group is believed to be more moist 

 than that of the Society Islands, and warmer; it was thought the 

 season was earlier, many of the fruits being farther advanced, making 

 full allowance for the difference in time. This we believe may be 

 owing to the extensive area of ocean (equal to 3,600,000 square 

 miles) lying a few degrees of latitude to the north of this group, the 

 temperature of which is several degrees elevated above that of the sea 

 surrounding the Tahitian Group. The extent and situation of this 

 area will be seen on the map which faces the title-page. 



The climate of this group may be classed as variable ; for one 

 situated within the tropics, it has a great deal of bad weather through- 

 out the year, and during the summer months is subjected almost 

 annually to violent hurricanes. In the winter, from April to No- 

 vember, the weather is more settled, the winds more moderate, and 

 calms often prevail. This group was visited by us in October, 1839, 

 and again in January and February, 1841, which enabled me to ob- 

 tain more accurate information of its climate ; this, however, has par- 

 ticular reference to the island of Upolu, the central one of the group, 

 and to the harbour of Apia, on its north side. The map of Upolu 

 (Hydrography, Vol. I.) will give a correct idea of its size and topo- 

 graphy. Apia is situated, with respect to the trade winds, on the lee, 

 or north side. The mean temperature during our first visit, October 

 and November, 1839, was, air 80'55, water 82'91; during the 

 second visit, in February, the air 79'94, water 82-61. The tempera- 

 ture on the south side of the island is a degree or two lower. The 

 variation of the temperature was from 72 to 98 ; that of the 

 water 6; from 80 to 86. From the register kept by the Rev. Mr. 

 Mills, the missionary at Apia, of which I was permitted to take a 

 copy, the mean temperature for the year 1838 was 79. The mean 

 solar radiation, sun 103'6, shade 92, difference 11'6; greatest 

 difference 26, least 1'5. 



To the kindness of William C. Cunningham, Esq., H. B. M. Vice- 

 Consul of Apia, as well as Mr. Lundy, of Tutuilla, I am indebted for 



