DEAR BOY: Three mails are now due from Holland, so that I have no letter from you to acknowledge; I write to you, therefore, now, as usual, by way of flapper, to put you in mind of yourself. Doctor Swift, in his account of the island of Laputa, describes some philosophers there who were so wrapped up and absorbed in their abstruse speculations, that they would have forgotten all the common and necessary duties of life, if they had not been reminded of them by persons who flapped them, whenever they observed them continue too long in any of those learned trances. I do not indeed suspect you of being absorbed in abstruse speculations; but, with great submission to you, may I not suspect that levity, inattention, and too little thinking, require a flapper, as well as too deep thinking? If my letters should happen to get to you when you are sitting by the fire and doing nothing, or when you are gaping at the window, may they not be very proper flaps, to put you in mind that you might employ your time much better? I knew once a very covetous, sordid fellow, who used frequently to say, "Take care of the pence; for the pounds will take care of themselves." This was a just and sensible reflection in a miser. I recommend to you to take care of the minutes; for hours will take care of themselves. I am very sure, that many people lose two or three hours every day, by not taking care of the minutes. Never think any portion of time whatsoever too short to be employed; something or other may always be done in it. While you are in Germany, let all your historical studies be relative to Germany; not only the general history of the empire as a collective body; but the respective electorates, principalities, and towns; and also the genealogy of the most considerable families. A genealogy is no trifle in Germany; and they would rather prove their two-and-thirty quarters, than two-and-thirty cardinal virtues, if there were so many. They are not of Ulysses' opinion, who says very truly, ----Genus et proavos, et qua non fecimus ipsi; Vix ea nostra voco. Good night. LETTER XX LONDON, November 24, O. S. 1747 DEAR BOY: As often as I write to you (and that you know is pretty often), so often I am in doubt whether it is to any purpose, and whether it is not labor and paper lost. This entirely depends upon the degree of reason and reflection which you are master of, or think proper to exert. If you give yourself time to think, and have sense enough to think right, two reflections must necessarily occur to you; the one is, that I have a great deal of experience, and that you have none: the other is, that I am the only man living who cannot have, directly or indirectly, any interest concerning you, but your own. From which two undeniable principles, the obvious and necessary conclusion is, that you ought, for your own sake, to attend to and follow my advice.