INTRODUCTION. 
XV 
austral stars ; geodesical measures, cfcc. Secondly, a treatise on 
the astronomical refractions in the torrid zone, considered as 
the effect of the decrement of caloric in the strata of the air ; 
thirdly, the barometric measurement of the Cordillera cf the 
Andes, of Mexico, of the province of Venezuela, of the kingdom 
of Quito, and of New Grenada ; followed by geological observa- 
tions, and containing the indication of four hundred and fifty- 
three heights, calculated according to the method of M. Laplace, 
and the new co-efficient of M. Ramond ; fourthly, a table of near 
seven hundred geographical positions on the New Continent ; 
two hundred and thirty-five of which have been determined by 
my own observations, according to the three co-ordinates of 
longitude, latitude, and height. 
II. JEijuinoctudplants collected in Mexico , in the island of Cuba, in 
the provinces of Caracas, Cwmana, and Barcelona, on the Andes of 
Mew Grenada, Quito, and Peru, and on the banks of the Bio Neqro 
the Orinoco, and the River Amazon. M. Bonpland has in this work 
given figures of more than forty new genera of plants of the 
torr J d classed according to their natural families. The 
methodical descriptions of the species are both in French and 
in Latin, and are accompanied by observations on the medicinal 
properties of the plants, their use in the arts, and the climate 
of the countries in which they are found. 
III. Monography of the Melastoma, Bhexia, and other genera of 
this order of plants, comprising upwards of a hundred and fifty 
species of melastomaceae, which we collected during the course of 
our expeditions, and which form one of the most beautiful orna- 
ments of tropical vegetation. M. Bonpland has added the plants 
ol the same family, which, among many other rich stores of 
natural history, M. Richard collected in his interesting expedi- 
tion to the Antilles and French Guiana, and the descriptions 
of which he has communicated to us. 
. Essay on the geography of plants, accompanied by a phy- 
sical table of the equinoctial regions, founded on measures taken 
from, the tmth degree of northern to the tenth deqree of southern 
latitude I have endeavoured to collect in one point of view the 
whole of the physical phenomena of that part of the New Con- 
tment comprised within the limits of the torrid zone from the 
evei ol the 1 acific-to the highest summit of the Andes ; namely, 
the vegetation, the animals, the geological relations, the cultiva- 
tion ot the soil, the temperature of the air, the limit of perpetual 
snow, the chemical constitution of the atmosphere, its electrical 
intensity, its barometrical pressure, the decrement of gravitation, 
the intensity of the azure colour of the sky, the diminution of 
light during its passage through the successive strata of the air, 
j.2, horizontal refractions, and tile heat of boiling water at 
different heights. Fourteen scales, disposed side by side with a 
