332 HALL’S EXCURSIONS, 
been able to cultivate the plants of the Paramos, even in 
Quito: the seeds refuse to germinate or the plants either 
perish before taking root, or preserve a brief and languishing 
existence. No doubt, other circumstances, such as atmo- 
spherical pressure and the action of light, co-operate, as 
Humboldt observes, with the effect of temperature; but 
these circumstances increase the difficulty of vegetable emi- 
gration. Another peculiarity of the elevated tropical regions, 
is the great heat of the sun’s rays, as compared with the 
shade. I have seen a thermometer placed on the grass, at 
Quito, rise to 120°, which is equal to its utmost range at the 
level of the sea; while in the shade its extreme range is 
60°—66°, in the high lands, and 80°—88° on the coast. It 
is for this reason that the heat seems more oppressive in Quito 
than in Guayaquil, there being frequently in the former a 
difference of more than 60° between the two sides of a street 
or wall, and these daily inequalities contrast more strongly 
with the annual uniformity of temperature already indicated, 
and still farther complicate the peculiarities of Andean 
vegetation. I have alluded to reflected heat, because it is 
that to which animal and vegetable life are subjected, and 
perhaps the only modification of the sun’s rays which can be 
accurately examined. 
It seems more easy to naturalize the vegetable productions 
of Europe in the regions of the Andes, than vice versá. 
European flowers adorn the gardens, and European vege- 
tables supply the tables of Quito, as of every part of the 
table lands. The introduction of the Cerealia is one of the 
few benefits conferred by the Spaniards on the New World. 
The Indigenes appear to have used only Maize, the Cheno- 
podium Quinua, the Potato, and the Ozalis tuberosa or Oka. 
Barley meal constitutes at present the chief article of their 
diet; for bread, though cheap, scarcely falls within their 
scanty resources. Oats and Hye are, as yet, unknown, 
though well adapted to many of the poorer soils, especially 
the sandy tracts round Ambato and Riobamba. The same 
cause which prevents the perfection of European fruit, limits 
