76 Professor Fournet’s Researches on the 
many local investigations in navigable rivers, yet from its portability and 
economy, and facility of erection in different places, we are satisfied it 
is calculated, with little expense or attention, on the part of the observ- 
ers, to lead to results of the most valuable description, in elucidating the 
theory and phenomena of the tides. 
Gro. BUCHANAN, Convener. 
ALEXANDER BRYSON. 
WILLIAM GALBRAITH. 
EDINBURGH, 1Oth June 1844. 
Researches on the Situation of Zones without Rain, and of 
Deserts. By M. J. Fournet, Professor in the Faculty of 
Sciences of Lyons. 
(Concluded from vol. xxxvii., p. 375.) 
From the straits of Magellan to the isthmus of Panama, 
the oceanic coast runs very nearly from south to north, and 
forms a low plain, which, in general, presents slightly arti- 
culated mountainous undulations only at the approach of the 
chain of the Andes. It is especially between Arequipa and 
Truxillo that this plain is narrowest, and hence results, pro- 
bably, the great humidity observable around Lima, compared 
with the country situated a little to the north or to the south 
of that place, a humidity whose characters we shall after- 
wards explain. At present let us see in what manner the 
principal facts exhibited by this region are connected. 
-Valparaiso (lat, 33° 7’ south) is situated in the sub-tropical 
zone of winter rains of the southern hemisphere (May to 
‘September). These rains become more and more rare to- 
-wards Cobija, in the tropic of Capricorn, where they begin to 
‘be entirely awanting; a state of matters which continues, 
more or less, as far as Guayaquil, in 2° of south lat.: there 
they are abundant during the months of winter, and cease 
in the middle of May; so that that place is situated in the 
zone of inter-tropical rains of the southern hemisphere ; but, 
leaving the Gulf of Guayaquil, in the forests of Choco and 
Esmeraldas, the arrangement rapidly changes, so that to the 
droughts of Tumbez and of Payta succeed a constant humi- 
dity and daily rains. 
