Distribuiion of Heat over the Globe. S 
sphere at 12,310 feet of absolute elevation ; and the mine of 
Santa Barbara, encircled with fine edifices, and placed a league 
to the south of Huancavelica, is a place fit for making regular 
observations, at the height of 14,509 feet, which is double that 
of the Hospice of St Gotliard. 
These examples are sufficient to prove how much our know- 
ledge of the higher regions of the atmosphere, and of the phy- 
sical condition of the world in general, will increase, when tlie 
cultivation of the sciences, so long confined to the temperate 
zone, shall extend beyond the tropics into those vast regions, 
where the Spanish Americans have already devoted themselves 
with such zeal to the study of physics and astronomy. In or- 
der to compare with the mean heat of temperate ' climates, the 
results which M. Bonpland and I obtained in the equinoctial 
regions from the plains to the height of 19,292 feet, it was ne- 
cessary to collect a great number of good observations made be- 
yond the parallels of 30® and 35®. I soon perceived how vague 
such a comparison was, if I selected places under the meridian 
of the Cordilleras, or with a more eastern longitude, and I there- 
fore undertook to examine the results contained in the most 
recent works. I endeavoured to find, at every 10® of latitude, 
but under different meridians, a small number of places whose 
mean temperature had been precisely ascertained, and through 
these, as so many fixed points, passed my isothermal lines or lines 
of equal heat. I had recourse, in so far as the materials have been 
made public, to those observations the results of which have been 
published, and I found, in the course of this easy, but long 
and monotonous labour, that there are many mean temperatures 
pointed out in meteorological tables, which, like astronomical 
positions, have been adopted without examination. Sometimes 
the results were in direct contradiction to the most recent obser- 
vations, and sometimes it was impossible to discover from 
whence they were taken. 
Many good observations were rejected, solely because the 
absolute height of the place where they were made ’was un- 
known. This is the case with Asia Minor, Armenia and Per- 
sia, and of almost all Asia ; and while the equinoctial part alone 
of the New World presents already more than 500 points, the 
greater number of 'wdiich are simple villages and hamlets, de- 
