This various reading, which I now conducted with discretion, was digested, according to the precept and model of Mr. Locke, into a large commonplace book; a practice, however, which I do not strenuously recommend. The action of the pen will doubtless imprint an idea on the mind as well as on the paper: but I much question whether the benefits of this laborious method are adequate to the waste of time; and I must agree with Dr. Johnson (Idler, No. 74), 'that what is twice read is commonly better remembered than what is transcribed'....
I will embrace this occasion of recommending to the young student a practice which about this time [1759] I myself adopted. After glancing my eye over the design and order of a new book, I suspended the perusal till I had finished the task of self-examination, till I had revolved, in a solitary walk, all that I knew, or believed, or had thought on the subject of the whole work, or of some particular chapter: I was then qualified to discern how much the author added to my original stock; and if I was sometimes satisfied by the agreement, I was sometimes armed by the opposition of our ideas.—E. Gibbon. Autobiography.
BESCRIBBLING WITH NOTES
Somewhat to aid the weakness of my memory and to assist her great defects; for it hath often been my chance to light upon books which I supposed to be new and never to have read, which I had, not understanding, diligently read and run over many years before, and all bescribbled with my notes: I have a while since accustomed myself to note at the end of my book (I mean such as I purpose to read but once) the time I made an end to read it, and to set down what censure or judgement I gave of it; that so it may at least at another time represent unto my mind the air and general idea I had conceived of the author in reading him.—Montaigne.
BOOKS TO BE MARKED
If the books which you read are your own, mark with a pen or pencil the most considerable things in them which you desire to remember. Then you may read that book the second time over with half the trouble, by your eye running over the paragraphs which your pencil has noted. It is but a very weak objection against this practice to say, 'I shall spoil my book;' for I persuade myself that you did not buy it as a bookseller, to sell it again for gain, but as a scholar, to improve your mind by it; and if the mind be improved, your advantage is abundant, though your book yields less money to your executors.—I. Watts. Logic.
UNDERSCORING
'On a subsequent evening, when I called by invitation to consult some other volumes, the conversation turned on the practice of underscoring books of study. Sir William spoke highly of the practice, as attended with many advantages, especially in the saving of time and labour. Intelligent underlining gave a kind of abstract of an important work, and by the use of different coloured inks to mark a difference of contents, and discriminate the doctrinal from the historical or illustrative elements of an argument or exposition, the abstract became an analysis very serviceable for ready reference. He mentioned that this principle had been carried to a ludicrous extreme in the publication of a coloured New Testament by an Anglicized German, Wirgmann by name.... In this book, entitled Divarication of the New Testament into Doctrine and History, the pages were all coloured, most of them parti-coloured, the doctrine being throughout visually separated from the history by this device; the doctrine being, if I remember rightly, blue, and the history red. The author expressed his belief that all the sects of Christendom had arisen from a confusion of these elements, and that his grand discovery in the "Divarication" would annihilate sects, establish pure Christianity as a sacred science, and become hereafter a Euclid in Theology.'—Sir William Hamilton. Life by J. Veitch.