SOUTH AMERICA.--The greater part of the tropical portion of the southern division of the western continent comes within the influence of the north-east Trades, which sweep up from the sea an enormous volume of watery vapour, which is precipitated gradually as the air current passes across the land. The second great factor in the determination of its climate is the position of the enormous mountain range of the Andes, quite close to the western coast, and of such a height as to cut off practically the last drops of moisture brought by the Trades, so as to leave the narrow belt of country between the Andes and the Pacific with a rainfall so scanty as to be in some instances almost negligible, as is the case with Lima, amounting to little more than an inch and a half in the year. So vast, however, is the amount of moisture imported by the Trades that the supply lasts out well, quite to the foot of the Andes, the rainfall of Manaos, half-way across, being rather greater than that of the east coast; but once the mountains are passed the change is abrupt and enormous. Unfortunately, however, when one sets one’s self to plot out the change as represented by a line of observations carried across the continent, one finds one’s self at once met by the difficulty that there is very little exact information to be obtained, as the all-absorbing interests of the ever-changing political barometer leaves the population little time to study the mercurial instrument, and they appear to be much fonder of playing with repeating rifles than with aneroids. Practically speaking, there is little exact information to be obtained for places at any distance from the coast, and on this account the tables given below refer almost exclusively to the littoral regions, and any attempt at anything beyond remarks of the most general character is out of the question. Quite at the southern boundary of our limits we have the first-class observatory of San Paolo, which although but little outside the geographical, tropical zone, enjoys a temperature which shows that we are rapidly leaving warm climates behind, for the climate is already milder than most localities in the subtropical zone of the old world. SAN PAOLO. 23° 33′ S.; 46° 38′ W. E.F., 2,400.