tion they confirm, as far as they
extend, the wonderful hypothesis he had entertained on this head,
and very nearly correspond, in their quantity, to the predictions he
published about fifty years since, long before he was acquainted with
any one observation made in those seas. The ascertaining the
variation in that part of the world is just now of more than
ordinary consequence, as the editors of a new variation chart, lately
published, for want of proper information, have been misled by
an erroneous analogy, and have even mistaken the very species of
variation in that of the northern ocean; for they make it westerly
where it is easterly, and have laid it down 12 deg. or 13 deg. different from
its real quantity.

This much it has been thought necessary to premise, with regard to the
hydrographical and geographical part of the ensuing work; which, it
is hoped, the reader will find, on perusal, much ampler and more
important than this slight sketch can well explain. But, as there
are hereafter interspersed, occasionally, some accounts of Spanish
transactions, and many observations relative to the dispositions
of the American Spaniards, and to the condition of the countries
bordering on the South Seas; and as herein I may appear to differ
greatly from the opinions generally established; I think it behoves me
particularly to recite the authorities I have been guided by in these
matters, that I may not be censured as having given way, either to a
thoughtless credulity on the one hand, or, what would be a much more
criminal imputation, to a wilful and deliberate misrepresentation on
the other.

Mr Anson, before he set sail upon this expedition, besides the printed
journals to these parts, took care to furnish himself with the best
manuscript accounts he could procure of all the Spanish settlements
upon the coasts of Chili, Peru, and Mexico. These he carefully
compared with the examinations of his prisoners, and the informations
of several intelligent persons who fell into his hands in the South
Seas. He had likewise the good fortune, in some of his captures, to
possess himself of a great number of letters and papers of a public
nature, many of them written by the viceroy of Peru to the viceroy
of Santa Fee, to the presidents of Panama and Chili, to Don Blass
de Lezo, admiral of the galleons, and to divers other persons in
considerable employments; and in these letters there was usually
inserted a recital of those they wer