all
look for them and not find them: after which, while you remain in the
same position, I will instruct you how to see them, and you shall see
them, and not merely wonder you did not see them before, but you shall
find it impossible to look at the spectrum without seeing them."

On looking as I was directed, notwithstanding the previous warning, I
did not see them; and after some time I inquired how they might be seen,
when the prediction of Mr. Herschel was completely fulfilled.

It was this attention to minute phenomena which Dr. Wollaston applied
with such powerful effect to chemistry. In the ordinary cases of
precipitation the cloudiness is visible in a single drop as well as in
a gallon of a solution; and in those cases where the cloudiness is so
slight, as to require a mass of fluid to render it visible, previous
evaporation, quickly performed on slips of window glass, rendered the
solution more concentrated.

The true value of this minute chemistry arises from its cheapness and
the extreme rapidity with which it can be accomplished: it may, in hands
like those of Wollaston, be used for discovery, but not for measure. I
have thought it more necessary to place this subject on what I consider
its true grounds, for two reasons. In the first place, I feel that
injustice has been done to a distinguished philosopher in attributing
to some of his bodily senses that excellence which I think is proved to
have depended on the admirable training of his intellectual faculties.
And, in the next place, if I have established the fact, whilst it
affords us better means of judging of such observations as lay claim to
an accuracy "MORE THAN HUMAN," it also opens, to the patient inquirer
into truth, a path by which he may acquire powers that he would
otherwise have thought were only the gift of nature to a favoured few.

APPENDIX, No. 1.

In presenting to my readers the account of the meeting of men of science
at Berlin, in the autumn of 1828, I am happy to be able to state, that
its influence has been most beneficial, and that the annual meeting
to be held in 1831, will take place at Vienna, the Emperor of Austria
having expressed a wish that every facility which his capital affords
should be given to promote its objects.

It is gratifying to find that a country, which has hitherto been
considered adverse to the progress of knowledge, should become convinced
of its value; and it is sincerely to be hoped, that every one o