An obvious question to be put to a historian is, What plan do you follow in making notes of your reading? Langlois, an experienced teacher and tried scholar, in his introduction to the "Study of History," condemns the natural impulse to set them down in notebooks in the order in which one's authorities are studied, and says, "Every one admits nowadays that it is advisable to collect materials on separate cards or slips of paper,"[42] arranging them by a systematic classification of subjects. This is a case in point where writers will, I think, learn best from their own experience. I have made my notes mainly in notebooks on the plan which Langlois condemns, but by colored pencil-marks of emphasis and summary, I keep before me the prominent facts which I wish to combine; and I have found this, on the whole, better than the card system. For I have aimed to study my authorities in a logical succession. First I go over the period in some general history, if one is to be had; then I read very carefully my original authorities in the order of their estimated importance, making copious excerpts. Afterwards I skim my second-hand materials. Now I maintain that it is logical and natural to have the extracts before me in the order of my study. When unusually careful and critical treatment has been required, I have drawn off my memoranda from the notebooks to cards, classifying them according to subjects. Such a method enables me to digest thoroughly my materials, but in the main I find that a frequent re-perusal of my notes answers fully as well and is an economy of time. Carlyle, in answer to an inquiry regarding his own procedure, has gone to the heart of the matter. "I go into the business," he said, "with all the intelligence, patience, silence, and other gifts and virtues that I have ... and on the whole try to keep the whole matter simmering in the _living_ mind and memory rather than laid up in paper bundles or otherwise laid up in the inert way. For this certainly turns out to be a truth; only what you at last _have living_ in your own memory and heart is worth putting down to be printed; this alone has much chance to get into the living heart and memory of other men. And here indeed, I believe, is the essence of all the rules I have ever been able to devise for myself. I have tried various schemes of arrangement and artificial helps to remembrance," but the gist of the matter is, "to keep the thing you are elaborating as much as possible actually _in_ your own living mind; in order that this same mind, as much awake as possible, may have a chance to make something of it!"[43]