PBODUCE OF COEN. 
497 
fine plantation belonging to Count Tovar, where we arrived 
on the evening of the fourteenth of February. The valley, 
which gradually widens, is bordered with hills of calcareous 
tula, called here tierra blatica. The scientific men of the 
country have made several attempts to calcine this earth 
mistaking it for the porcelain earth proceeding from decom- 
posed strata of feldspar. We stayed some hours with a 
very intelligent family, named Ustariz, at Concesion. Their 
house, which contams a collection of choice books, stands 
on an eminence, and is surrounded by plantations of coffee 
and sugar-cane. A grove of balsam-trees (balsamo*) gives 
coolness and shade to this spot. It was gratifying to observe 
the great number of scattered houses in the valley inhabited 
by freedmen. In the Spanish colonies, the laws, the insti- 
tutions, and the manners, are more favourable to the liberty 
of the negroes than in other European settlements. 
San Mateo, Turmero, and Maracay, are charming vil- 
lages, where everything denotes the comfort of the inha- 
bitants. We seemed to be transported to the most indus- 
trious districts of Catalonia. Near San Mateo we find the 
last fields of wheat, and the last mills with horizontal 
hydraulic wheels. A harvest of twenty for one was ex- 
pected ; and, as if that produce were but moderate, I was 
asked whether corn yielded more in Prussia and in Poland. 
By an error generally prevalent under the tropics, the pro- 
duce of grain is supposed to degenerate in advancing 
towards the equator, and harvests are believed to be more 
abundant in northern climates. Since calculations have 
been made on the progress of agriculture in the different 
zones, and on the temperatures under the influence of which 
corn will flourish, it has been found that, beyond the 
latitude of 45°, the produce of wheat is nowhere so con- 
siderable as on the nortnern coasts of Africa, and on the 
table-lands of New Grenada, Peru, and Mexico. Without 
comparing the mean temperature of the whole year, but 
only the mean temperature of the season which embraces 
the corn cycle of vegetation, we find for three months of 
summer ,f in the north of Europe, from 15° to 19° ; iu Par- 
* Amyris elata. 
“t The mean heat of the summers of Scotland in the environs ol 
VOL. I. 2 K 
