56 
Geography of the Gaboon . 
says Dr. Ford, “less than in many salubrious 
localities in other parts of the world.” 
•Upon the Gaboon the wet seasons are synchro¬ 
nous with the vertical suns at the vernal and 
autumnal equinoxes. “ The rainy season of a place 
within the tropics always begins when the sun has 
reached the zenith of that place. Then the trade- 
winds, blowing regularly at other seasons, become 
gradually weaker, and at length cease and give 
way to variable winds and calms. The trade-wind 
no longer brings its regular supply of cooler, drier 
air; the rising heats and calms favour an ascending 
current ” (in the sea-depths, I may add, as well as 
on land), “ which bears the damp air into the upper 
regions of the atmosphere, there to be cooled, and 
to occasion the heavy down-pour of each afternoon. 
The nights and mornings are for the most part 
bright and clear. When the sun moves away from 
the zenith, the trade-winds again begin to be felt, 
and bring with them the dry season of the year, 
during which hardly ever a cloud disturbs the 
serenity of the skies. 
“ Between the tropical limits and the equator, 
however, the sun comes twice to the zenith of each 
place. If now, between the going and coming of 
the sun, from the Line to its furthest range, a 
sufficient pause intervenes, or if the sun’s tem¬ 
porary distance from the zenith is great enough, 
the rainy season is divided into two portions, 
