phism of equivocation is when we use words of an ambiguous or double sense, and draw inferences in one sense, of which the proposition is capable only in the other.

7. Petitio principii, or begging the question, is the supposition of what is not granted, or a supposed proof, by stating the question in other words. The Reductio ad absurdum is when the truth of a proposition is proved by showing the absurdity of a contrary supposition.

S. A false induction is when general deductions are made from a limited number of experiments or facts. The fallacia accidentis is when we draw inferences in regard to the nature of a thing, from circumstances only temporary or accidental. The Ignorantia elenchi is a mistake of the question, or when one thing is proved instead of another.

Select Books on Logic.

Watts' I.ogic, 8vo. or 12mo. Duncan's Logic, 12mo. and Collard's Praxis of Logic, 12mo. This last book is a convenient substitute for the larger treatises of Watts and Duncan. Barron's Logic, in his Lectures, 2 vols. 8vo. Locke's Essay on the Human Understanding, 2 vols. 8vo.; or for younger minds, Mr. Wynne's "Abridgment,"

12mo.

SECT. 1.

CHAP. III. - MNEMONICS.

GENERAL OBSERVATIONS UPON MEMORY.

1. ALL the abilities of the mind borrow from memory their beauty and perfection; without this, the other faculties of the soul are almost useless. To what purpose are all our labours in knowledge and wisdom, if we want memory to preserve and use what we have acquired? What avail all other intellectual or spiritual improvements, if they are lost as soon as they are obtained? Memory alone enriches the mind, by preserving what our labour and industry have collected. Without memory, there can be neither knowledge, nor arts, nor sciences. Without the assistance and influence of this power, mankind would experience no improvement in virtue, in morals, or in religion. The soul of man would be but a poor, destitute, naked being, without memory. If we except the fleeting ideas of the moment, it would present an everlasting blank.

Hail, Memory hail! in thy exhaustless mine,
From age to age unnumber'd treasures shine!
Thought and her shadowy brood thy call obey,
And Place and Time are subject to thy sway!
Thy pleasures most we feel when most alone,
The only pleasures we can call our own!
Lighter than air Hope's summer visions die,
If but a fleeting cloud obscure the sky;
If but a beam of sober reason play,

Lo! Fancy's fairy frost-work melts away!

2. It is often found, that a fine genius has but a feeble memory for, where the genius is bright, and the imagination vivid, the power of memory may be too much neglected, and lose its improvement. An active fancy readily wanders over a multitude of objects, and is continually entertaining it with new and transitory images. It runs through a number of new scenes, or new pages, with pleasure, but without due attention; and seldom suffers itself to dwell upon any of them, long enough for the mind to receive a deep impression, or for the remembrance of the subject to be lasting. Consequently, many persons of very bright parts, and active spirits, have but short and narrow powers of recollection;-possessing riches of their own, they are not solicitous to borrow from the stores of others. When the memory has been almost constantly employed in making new acquirements, and when there has not been a judgment sufficient to distinguish what was fit to be remembered, and what was idle, useless, or needless, the mind has been filled with a wretched heap of words or ideas. In this case, the soul had large possessions, but no true riches. Whatever, as MILTON says, old TIME, with his HUGE DRAG NET, has conveyed down to us, along the stream of ages; whether it be SHELLS, or SHELL-FISH; JEWELS, or PEBBLES; STICKS, or STRAWS; SEA-WEEDS, Gr MUD;-all is treasured up indiscriminately, by those persons who have not the judgment to determine what is to be remembered, and what is to be forgotten. How many excellent judgments and reasonings are framed in the mind

* In all these cases, (says Mr. Locke), ideas in the mind quickly fade, and often vanish quite out of the understanding, leaving no more footsteps or remaining characters of themselves, than shadows de, fiying over fields of corn; and the mind is as void of them, as if they had never been there.

of a wise and studious man, in a length of years! How many worthy and admirable notions has he possessed in life, both by his own reasonings, and by his prudent recollections in the course of his reading! But, alas! how many thousands of them vanish, and are lost, for want of a happy and retentive memory.

3. MR. LOCKE, speaking of the continual decay of our ideas, beautifully observes, "The ideas, as well as children, of our youth, often die before us: and our minds represent those tombs, to which we are approaching; where though the brass and marble remain, yet the inscriptions are effaced by time, and the imagery moulders away. The pictures drawn in our minds are laid in fading colours, and if not sometimes refreshed, vanish and disappear. How much the constitution of our bodies, and the make of our animal spirits are concerned in this, and whether the temper of the brain makes this difference, that, in some, it retains the characters drawn on it like marble, in others like freestone, and in others, little better than sand; I shall not here inquire though it may seem probable, that the constitution of the body does sometimes influence the memory; since we oftentimes find a disease quite strip the mind of all its ideas, and the flames of a fever, in a few days, calcine all those images to dust and confusion, which seemed to be as lasting as if graved in marble."

4. A good memory has these qualifications: (1.) It is ready to receive and admit, with perfect ease, the various ideas of words and things which are learned or taught. (2.) It is copious enough to treasure up these ideas in great number and variety. (3.) It is sufficiently strong, to retain, for a considerable time, those words or thoughts which are committed to its care. (4.) It possesses the power of suggesting and recollecting, from the abundance of its store, words or thoughts proper for every occasion in life.

SECT. II. RULES FOR IMPROVING THE MEMORY.

Many rules have heen given for the regulation of this important faculty; the following, if attentively practised, will conduce much to the solid and lasting improvement of the memory.

1. Temperance in eating, drinking, and sleep. The memory depends much upon the state of the brain, and

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therefore what is hurtful to the latter, must be prejudicial to the former. Too much sleep clouds the brain, and too little overheats it; therefore, either of these extremes ought to be avoided. Intemperance of all kinds, and excess of passion, have the same ill effects.

2. A clear and distinct apprehension of what we wish to remember. We should understand the subject thoroughly, and fix our view particularly upon its importance. We should also disengage ourselves from all other things. We must not plunge ourselves into any other business or study--amusement or recreation-immediately after we have attended upon instruction. should endeavour to recollect the subjects we have heard discussed, that they may not be washed away from the mind by a torrent of other occurrences, or engagements.

We

3. An abridgment of a good book is, sometimes, a very useful exercise. In general, when we would preserve the doctrines, sentiments, or facts, that occur in reading, we should lay the book aside, and put them in our own words. This practice will give accuracy to our knowledge-accustom us to recollection-improve us in the use of language -and enable us so thoroughly to comprehend the thoughts of others, as to make them, in some measure, our own.

4. Method and regularity are essentially necessary. Those things are best remembered, the parts of which are methodically disposed and mutually connected. A regular discourse makes a more lasting impression upon the hearer than a parcel of detached sentences, and gives a better exercise to his rational powers. This forcibly evinces the necessity of conducting our studies, and all our affairs, according to a regular plan or method. If this is not done, confusion is a certain consequence.

The success attending the practice of this rule is well exemplified by MR. ADDISON, who says, "Medallists, upon the first naming of an emperor, will immediately tell you his age, family, and life. To remember where he enters in the succession, they only consider in what part of the cabinet he lies; and by running over in their thoughts such a particular drawer, will give you an account of all the remarkable parts of his reign.' If our ideas were arranged with equal method and order, the mind would turn to them with the like facility. With a general knowledge

of the contents of a library, and of the manner in which the books are distributed, a person may, even when absent from the spot, determine, with certainty, the situation of any particular book.*

5. Repetition and Review. When a person is hearing a sermon, or a lecture, he should endeavour to recollect the several beads of it, from the beginning, two or three times before the discourse is finished. The omission or the loss of a few sentences is amply compensated by preserving in the mind the method and order of the whole discourse, in all its most important branches. Discoursing with our companions on what we have been reading, or teaching it to our younger friends, is 'an excellent mode of repetition, and contributes, more than any other, perhaps, to assist the memory. "Docendo disco:" If we would recollect what we hear, or intend to speak, we must make an abstract of it, and review it often.

The memory gains great advantage by having the objects of our learning drawn out into schemes or tables. The situation of the several parts of the earth is better learned by one day's consultation with the terrestrial globe, than by merely reading the description of their situation a hundred times over in books of geography.. Writing what we wish to remember once, and giving it due attention, will fix it more in the mind than reading it se veral times. What we have seen is not so soon forgotten as what we have only heard. What Horace affirms of the mind or passions is not less applicable to the memory:

Sounds which address the ear are lost and die

In one short hour; but that which strikes the eye
Lives long upon the mind; the faithful sight
Engraves the knowledge with a beam of light.

6. Rhyme. The memory of useful things may receive considerable aid, if they are thrown into verse. For the numbers and measures, and rhyme, according to the poesy

* The well-known anecdote of MAGLIABECHI, librarian to the Grand Duke of Tuscany, Cosmo III. is an apt and amusing illustration of this fact. The Grand Duke having asked Magliabechi whether he could procure a book that was particularly scarce, he replied, "No, Sir, it is impossible, for there is but one in the world, that is in the Grand Signior's library at Constantinople, and is the seventh book on the second shelf, on the right hand side as you go in."