There is a memory in _extension_ that holds a long string of words and ideas together. Its value is to get readily at anything occurring in a certain train, as in a given book. It is the memory of easy reference. There is also a memory of _intension_, that takes a strong grasp of brief expressions and thoughts, and brings them out for use, on the slightest relevancy. The two modes interfere with each other's development; we cannot be great in both; while, for original force, the second is worth the most: it extracts and resets gems to tesselate our future structures; it constitutes depth as against fluency. To commit poetical passages to memory is a valuable contribution to our stock of material for emotional resuscitation in after years. It also aids in adorning our style, even although we may not aspire to compose in poetry. But the burden of holding the connection of a long poem should be eschewed. Children can readily learn a short psalm or hymn, and can retain it in permanence; but to repeat the 119th psalm from the beginning is the mere _tour-de-force_ of a strong natural memory, and a waste of power; just as much as committing an entire book of the Aeneid or of Paradise Lost. * * * * * [MAKING ABSTRACTS.] 3. Making Abstracts.--This is the plan of studying that most advances our intelligent comprehension of any work of difficulty, and also impresses it on the memory in the best form. But there are many ways of doing it; and beginners, from the very fact that they are beginners, are not competent to choose the best. If a book has an obvious and methodical plan in itself, the reader can follow that plan, taking down the leading positions, selecting some of the chief examples or illustrations, giving short headings of chapters and paragraphs, and thus making a synopsis, or full table of contents. All this is useful. The memory is much better impressed through the exertion of picking, choosing, and condensing, than by copying _verbatim_; and the plan or evolution of the whole is more fully comprehended. But, if a work does not easily lend itself to a methodical abstract, the task of the beginner is much harder. To abstract the treatises of Aristotle was fitting employment for Hobbes. The "Wealth of Nations" is not easy to abstract; but, at the present day, it would not be chosen as the Text-book-in-chief for Political Economy: as a third or fourth work to be perused at a reading pace, it would have its proper effect. The best studious exercise upon it would be to mark the agreements and disagreements with the newer authority, the weak and strong points of the exposition, and the perennial force of a certain number of the propositions and examples. Many parts could be skipped entirely as not even repaying historical study. Yet, as the work of a great and original mind, its interest is perennial.