To every reader nothing can be more important than that faculty of the mind which we call memory. The retentive memory instinctively stores up the facts, ideas, imagery, and often the very language found in books, so clearly that they become available at any moment in after life. The tenacity of this hold upon the intellectual treasures which books contain depends largely upon the strength of the impression made upon the mind when reading. And this, in turn, depends much upon the force, clearness and beauty of the author's style or expression. A crude, or feeble, or wordy, redundant statement makes little impression, while a terse, clear, well-balanced sentence fixes the attention, and so fastens itself in the memory. Hence the books which are best remembered will be those which are the best written. Great as is the power of thought, we are often obliged to confess that the power of expression is greater still. When the substance and the style of any writing concur to make a harmonious and strong impression on the reader's mind, the writer has achieved success. All our study of literature tends to confirm the conviction of the supreme importance of an effective style. We must set down a good memory as a cardinal qualification of the librarian. This faculty of the mind, in fact, is more important to him than to the members of any other profession whatever, because it is more incessantly drawn upon. Every hour in the day, and sometimes every minute in the hour, he has to recall the names of certain books, the authors of the same, including both their surnames and Christian or forenames, the subjects principally treated in them, the words of some proverb or quotation, or elegant extract in poetry or prose, the period of time of an author or other noted person, the standard measurements and weights in use, with their equivalents, the moneys of foreign nations and their American values, the time of certain notable events in history, whether foreign or American, ancient or modern, the names and succession of rulers, the prices of many books, the rules observed in the catalogue, both of authors and subjects, the names and schools of great artists, with their period, the meaning in various foreign languages of certain words, the geographical location of any place on the earth's surface, the region of the library in which any book is located--and, in short, an infinitude of items of information which he wants to know out of hand, for his own use, or in aid of Library readers or assistants. The immense variety of these drafts upon his memory seldom perplexes one who is well endowed with a natural gift in that direction. In fact, it seems actually true of such minds, that the more numerous the calls upon the memory, the more ready is the response.