MEMORY. 'Phis is one name for the great and distinctive fact of mind, namely, the power of retaining impressions made through the senses, and of reviving them at after times without the,originals, and by mental forces alone. The conditions of this power have been already stated (see ASSOCIATION OF IDEAS, HABIT). We shall advert here to some of the arts and devices that have been propounded from time to time, for aiding our recollection in the various kinds of knowledge.
Perhaps the commonest remark on this subject is, that memory depends on atten tion, or that the more we attend to a thing, the better we remember it. This is true with -reference to any special acquisition: if WC direct the forces of the mind upon one point, we shall necessarily give that point the benefit of the concentration, but this does not ,i,ffect memory as a whole: we merely take power from one thing to nive it to anothei. Memory at large can be improved only by increasing the vigor and freshness of the -nervous system, and by avoiding. all occasions of exhaustion, undue excitement, and other causes of nervous waste. We may do this by general constitutional means, or by stimulating the brain at the expense of the other functions; this last method is, how ever, no economy in the end. Every man's system has a certain fund of plastic power, which may be husbanded, but cannot be materially increased on the whole; the powei toeing „greatest in.early life., and diniinishing with advancing years. If it is strongly drawn upon for one class of acquisitions, we must not expect it to be of equal avail for others.
But there may be ways and means of presenting and arranging the matters of our knowledge so as to make them retained at a smaller cost of the plastic power of the brain. These include the arts of teaching, expounding, and educating in general, and zits° certain more special devices commonly known as the arts of memory, or mne monics. A brief account of these last may be given here.
The oldest method of artificial memory is said to have been invented by the Greek poet Simonides, who lived in the 5th c. B. C. It is named the topical, or locality tnemory, from the employment of known places as the medium of recollection. As.given by Quintilian it is in substance as follows: You choose a very spacious and diversely arranged place—a large house, for instance, divided into several apartments. You impress on the mind with care whatever is remarkable in it; so that the mind niay run through all the parts without hesitation and delay. Then if you have to remember a series of ideas, you place the first in the hall, the second in the parlor, and so on with the rest, _going over the windows, the chambers, to the statues and several objects. Then when you 'wish to recall the succession, you commence going over the house in the order fixed, and in connection with each apartment you will tind the idea that you attached to it. The principle of the method is that it is more easy for the mind to associate a thought with a well-known place than to associate the same thought with the next thought without any medium whatever. Orators are said to have used the method for remembering their
speeches. The method has been extensively taught by "writers'on mnemonics in modern times. Probably for temporary efforts of memory it may be of some use; the doubtful point atlways is whether the machinery of such systems is not more cumbrous than helpful.
Much labor has been spent-on mnemonic devices for assisting in the recollection of numbers, one of the hardest efforts of memory. The principal method for this purpose is to reduce the numben to words, by assigning a letter for each of the ten ciphers. This method was reduced to system by Gregor von Feinaigle, a German monk, and was taught by him in various parts of Europe, and finally published in 1812. He made a -careful choice of the letters for representing the several figures, having in view some :association between the connected couple, for more easy recollection. For the figure 1, he used the letter t, as being a single stroke; for 2, n, as being two strokes combined; 3, in, three strokes; 4, r, which is found in the word denoting " four" in the European languages; 5, /, froin the Roman numeral L, signifying fifty, or five tens; 6, sl, because the written d resembles 6 reversed; 7, k, because k resembles .two 7's joined at top; in place of this figure is also used on occasion g, q, c (hard) as all belonging to the guttural class of k; 8, b, from a certain amount of similarity, also to, for the same reason, _and sometimes v, or the half to; 9 is p, from similarity, and also f, both of which are united in the word puff, which proceeds from a pipe, like a 9 figure; 0 is s, x, or z, because it resembles in its roundness a. grindstone, which gives out a hissing noise like these letters. The letters of the alphabet not employed in .representing figures are to be used in -combination with these, but with the understanding that they have no meaning of them :selves. Suppose, then, that a number is given, say 547; 5 is /, 4 is r, 7 is k; which makes r,k; among these letters we insert an unmeaning vowel, as a, to make up an intelligible word Lank, which remains iu the memory far more easily than the numerical form. In making up the words by the insertion of the unmeaning or dumb letters, we should also have regard to some connection with the subject that the number refers to, as, for example, in 'chronology. Thus, America was discovered in 1492; the letters' here are t, r, p, n; they may- be made into TO BariNe, because that discovery led to rapine by the first Spaniards. 'There is, of course, great room for ingenuity in the formation of these suggestive words. Also, a series of numbers may be joined together in 'some intelligible, sentence which ,can be easily remembered. Such combinations, however, should be formed once for all in the case of any important series of numbers, as the dates of our sovereigns and other historical epochs. It is too much to expect pupils to construct these felicitous combina tions. Feinaigle combined the topical method with the above plan in fixing a succession. .of numbers in the memory.