present
day. You cannot even make intelligent inquiries, and betray a graceful,
because unwilling ignorance, without some degree of general knowledge of
science.

Among the numerous elementary works which make the task of
self-instruction pleasant and easy, none can excel, if any have
equalled, the "Scientific Dialogues" of Joyce. In these six little
volumes, you will find a compendium of all preliminary knowledge; even
these, however, easy as they are, require to be carefully studied. The
comparison of the text with the plates, the testing for yourself the
truth of each experiment, (I do not mean that you should practically
test it, except in a few easy cases, for your mind has not a sufficient
taste for science to compensate for the trouble,) will furnish you with
very important lessons in the art of fixing your attention.

"Conversations on Natural Philosophy," in one volume, by a lady, is
nearly as simple and clear as the "Scientific Dialogues;" it will serve
usefully as a successor to them. It is a great assistance to the memory
to read a different work on the same subject while the first is still
fresh in your mind. The sameness of the facts gives the additional force
of a double impression; and the variation in the mode of stating them,
always more striking when the books are the respective works of a man
and of a woman, adds the force of a trebled impression, stronger than
the two others, because there is in it more of the exercise of the
intellect, that is, on the supposition that, in accordance with the
foregoing rules, you should think over each respective statement until
you have reconciled them together by ascertaining the cause of the
variation.

I shall now proceed to those lighter branches of literature which are
equally necessary with the preceding, and which will supply you with the
current coin of the day,--very necessary for ordinary intercourse,
though, in point of real value, far inferior to the bank-stock of
philosophic and scientific knowledge which it is to be your chief object
to acquire. History is the branch of lighter literature to which your
attention should be specially directed; it provides you with
illustrations for all philosophy, with excitements to heroism and
elevation of character, stronger perhaps than any mere theory can ever
afford. The simplest story, the most objective style of narrative, will
be that best fitted to answer these purposes. Your own philosophic
deductions wi