H 
S U M A T R A. 
farther pemnfitla of India, where the kingdom ofSiam lies, experiences 
at the fame time the eflxfts of oppofite feafons, the weftern fide, in the Bay 
of Bengal, being expofed for half the year to continual rains^ whilft on 
the eaftern lide the fineft weather is enjoyed ; and fo on th^ different 
coafts of IndoRanj the monfoons exerc their influence alternately ; the 
one remaining ferene and undifturbed^ whilft the other is agitated by 
ftorms. Along the coaft of Coromandel^ the change, or breaking up 
of the monfoons, as it is called, fcldom fails of being attended with the 
tnoft violent gules of wind. 
On the weft coaft of Sumatra, the S. E. monfoon or dry feafon, be* 
gms about May, and ftackcns in September : the N, W. monfoon be* 
^'ms about November, and the hard rains ceafe about March- The 
Ktivc ort gradually there; 
f he months of April and May, 0^toI>er and November, generally afford* 
ing weather and winds variable and uncertain. 
The caufes of thefe periodical winds have been particularly pointed 
out by fcveral able wntersj and their dire£tions accounted for in the dif- 
ferent parts of the globe where they prevail. I fliall therefore juft fum- 
marily mention, that the diurnal revolution of the earth from weft to 
eaft, or the virtual receding of the fun in a contrary direction, would, 
if that luminary always remained In the equatorial figns, produce a ge* 
neral call wind, as the current of air naturally follows the rarefaction cau- 
fed in the aimofphcre by its ray^ "R"*- tK<. Aui gradually changes his 
fituation, or declination, from north to fouth, and again from fouth to 
north, the current of air by the fame law of nature, follows him like wife 
in this courfe, and acquires a motion compounded of thefe two directions, 
producing a north eaft wind, when he is to the fouthward of the 
line, and a fouth eaft when he is to the northward. But it alfo happens, 
as is proved by uniform experiencej that the periodical winds are infiu* 
enced in their courfe, by the direction of the coaft s near which they 
blow, and incline to a parrallelifm therewith; in confcquence of which, the 
K. E. monlbon is changed to N. W* on the Sumatra coaftj which has 
that 
