We not only have ideas of memory, individually taken; that is, separately, each by itself; as in the instances which we have just been considering: we have also trains of such ideas. All narratives of events which ourselves have witnessed are composed of such trains. The ideas forming those trains do not follow one another in a fortuitous manner. Each succeeding idea is called up by the one which {326} precedes it; and every one of these successions takes place according to a law of association. After a lapse of many years, I see the house in which my father died. Instantly a long train of the circumstances connected with him rise in my mind: the sight of him on his death-bed; his pale and emaciated countenance; the calm contentment with which he looked forward to his end; his strong solicitude, terminating only with life, for the happiness of his son; my own sympathetic emotions when I saw him expire; the mode and guiding principles of his life; the thread of his history; and so on. In this succession of ideas, each of which is an idea of memory, there is not a single link which is not formed by association; not an idea which is not brought into existence by that which precedes it. Whensoever there is a desire to fix any train in the memory, all men have recourse to one and the same expedient. They practise what is calculated to create a strong association. The grand cause of strong associations is repetition. This, accordingly, is the common resource. If any man, for example, wishes to remember a passage of a book, he repeats it a sufficient number of times. To the man practised in applying the principle of association to the phenomena in which it is concerned, the explication of this process presents itself immediately. The repetition of one word after another, and of one idea after another, gives the antecedent the power of calling up the consequent from the beginning to the end of that portion of discourse, which it is the purpose of the learner to remember.