vision, their astronomers cannot have had a telescopic power of sight;
for they did not discover the satellites of Jupiter, which are often
seen with the naked eye at Oormeeah, in Persia, and sometimes, as I can
testify by personal observation, at Cairo.]

This exercise of the eye I desire to promote, and, next to moral and
religious doctrine, I know no more important practical lessons in this
earthly life of ours--which, to the wise man, is a school from the
cradle to the grave--than those relating to the employment of the sense
of vision in the study of nature.

The pursuit of physical geography, embracing actual observation of
terrestrial surface, affords to the eye the best general training that
is accessible to all. The majority of even cultivated men have not the
time and means of acquiring anything beyond a very superficial
acquaintance with any branch of physical knowledge.

Natural science has become so vastly extended, its recorded facts and
its unanswered questions so immensely multiplied, that every strictly
scientific man must be a specialist, and confine the researches of a
whole life within a comparatively narrow circle. The study I am
recommending, in the view I propose to take of it, is yet in that
imperfectly developed state which allows its votaries to occupy
themselves with broad and general views attainable by every person of
culture, and it does not now require a knowledge of special details
which only years of application can master. It may be profitably pursued
by all; and every traveller, every lover of rural scenery, every
agriculturist, who will wisely use the gift of sight, may add valuable
contributions to the common stock of knowledge on a subject which, as I
hope to convince my readers, though long neglected, and now