I perceive he read a great deal at Ruppin: what Books I know not specially: but judge them to be of more serious solid quality than formerly; and that his reading is now generally a kind of studying as well. Not the express Sciences or Technologies; not these, in any sort,--except the military, and that an express exception. These he never cared for, or regarded as the noble knowledges for a king or man. History and Moral Speculation; what mankind have done and been in this world (so far as "History" will give one any glimpse of that), and what the wisest men, poetical or other, have thought about mankind and their world: this is what he evidently had the appetite for; appetite insatiable, which lasted with him to the very end of his days. Fontenelle, Rollin, Voltaire, all the then French lights, and gradually others that lay deeper in the firmament:--what suppers of the gods one may privately have at Ruppin, without expense of wine! Such an opportunity for reading he had never had before. In his soldier business he is punctual, assiduous; having an interest to shine that way. And is, in fact, approvable as a practical officer and soldier, by the strictest judge then living. Reads on soldiering withal; studious to know the rationale of it, the ancient and modern methods of it, the essential from the unessential in it; to understand it thoroughly,--which he got to do. One already hears of conferences, correspondences, with the Old Dessauer on this head: "Account of the Siege of Stralsund," with plans, with didactic commentaries, drawn up by that gunpowder Sage for behoof of the Crown-Prince, did actually exist, though I know not what has become of it. Now and afterwards this Crown-Prince must have been a great military reader. From Caesar's COMMENTARIES, and earlier, to the Chevalier Folard, and the Marquis Feuquiere; [_Memoires sur la Guerre_ (specially on the Wars of Louis XIV., in which Feuquiere had himself shone): a new Book at this time (Amsterdam, 1731; first COMPLETE edition is, Paris, 1770, 4 vols. 4to); at Ruppin, and afterwards, a chief favorite with Friedrich.] from Epaminondas at Leuctra to Charles XII. at Pultawa, all manner of Military Histories, we perceive, are at his finger-ends; and he has penetrated into the essential heart of each, and learnt what it had to teach him. Something of this, how much we know not, began at Ruppin; and it did not end again.