SIR,--The acknowledgment of your favor of July 15th, and thanks for the Review which it covered of Mr. Pickering's Memoir on the Modern Greek, have been delayed by a visit to an occasional but distant residence from Monticello, and to an attack here of rheumatism which is just now moderating. I had been much pleased with the memoir, and was much also with your review of it. I have little hope indeed of the recovery of the ancient pronunciation of that finest of human languages, but still I rejoice at the attention the subject seems to excite with you, because it is an evidence that our country begins to have a taste for something more than merely as much Greek as will pass a candidate for clerical ordination. You ask my opinion on the extent to which classical learning should be carried in our country. A sickly condition permits me to think, and a rheumatic hand to write too briefly on this litigated question. The utilities we derive from the remains of the Greek and Latin languages are, first, as models of pure taste in writing. To these we are certainly indebted for the national and chaste style of modern composition which so much distinguishes the nations to whom these languages are familiar. Without these models we should probably have continued the inflated style of our northern ancestors, or the hyperbolical and vague one of the east. Second. Among the values of classical learning, I estimate the luxury of reading the Greek and Roman authors in all the beauties of their originals. And why should not this innocent and elegant luxury take its preëminent stand ahead of all those addressed merely to the senses? I think myself more indebted to my father for this than for all the other luxuries his cares and affections have placed within my reach; and more now than when younger, and more susceptible of delights from other sources. When the decays of age have enfeebled the useful energies of the mind, the classic pages fill up the vacuum of _ennui_, and become sweet composers to that rest of the grave into which we are all sooner or later to descend. Third. A third value is in the stores of real science deposited and transmitted us in these languages, to-wit: in history, ethics, arithmetic, geometry, astronomy, natural history, &c.