A. J. Downing, Esq.- Sir: I am much obliged to you for all you are pleased to say on the cultivation of the vine in general, and especially with respect to the universal failure, in this country, in cultivating the European varieties in the open air; though I have been acquainted with those same prevailing opinions for a great many years. I can add to the authorities cited by you, that of the late President Thomas Jefferson, who stated to me so far back as 1819, bis utter failure, and his inability to succeed in cultivating the European varieties at Monticel-lo. Professor Caldwell, at Chapel Hill, N. C, has also failed. Many more could be added, such as Michacx's (the botanist,) experiment in South Carolina, which equally proved a failure. Herbemont in South, and Laspetre in North Carolina, met only partial success, so far as I can learn. Still, so far back as 1821 and 1822,I succeeded in cultivating them in Fauquier county, Virginia, on the farm of Dr. R. Peyton. I understand that Judge John Scott has had since, great success in the same county.

Wherever I have been, I have found that the idea you entertain, about European varieties not succeeding in "this country" in the open air, is every where prevailing. "The thing is impossible," you say; certainly in the state of New-York. Though Mr. N. Longworth did not succeed, as he did me the honor to inform me at Cinc'nnati, still that is no reason for my trial not succeeding 6° of latitude farther south.

I may here state that the fig tree and almond tree, do well with us in the open air, and that las, ripened in the open field, by the 10th of last August, i. e., in 145 days, and that they were as good as any I have ever eaten in Corsica, celebrated for its climate for the culture of the vine. It must be remarked that this early degree of perfect maturity, was produced by vines that eight months previously were not as yet planted in the sand hills of North Carolina, but were on the ocean, on their way to this, their now adopted country.

In a letter written more than 17 months ago, to Mr. Thomas Ewbank, at his own request, which will soon be published in the Patent Office Report, you will see, sir. that I do not differ with you as to the importance of the method of seedlings, in order to obtain new varieties best suited to this country. It may be gratifying to you to know that your hint of resorting to seedlings has long been anticipated by me.

As to the grape-vines being exhausted by long cultivation or neglect, the experience of France Vigninicole abundantly proves it. Let us see, for instance, what Le Comte de Gasparin says. "We must provide for this state of things, (old age,) which threatens its future fecundity. There exists two systems. The first is to root up the vine, which tends to its decripitude," &c; and again: "In about 15 years, more or less, the vintage of the vineyard diminishes, and from this epoch, the weakness which at first was but little perceptible, continues, and ends by becoming considerable. A vineyard which at first produced 18 hectoliters, with the same care and manures will only yield 9 or 10 when the vineyard will be 30 or 40 years old." Vol. iv, p. 674.

I cannot anticipate, and will not now state what are my future expectations. I have planted European grape-vines in the open air, in the hope to succeed, though you say it is in vain. "Time alone can determine," I say. I shall take great pleasure in informing you of the results of my trial.

Tour recommendation with respect to the cultivation of the European vines in northern latitudes, is perfectly right, but does not hold good for my locality, in latitude 34°. The isothermal line fortunately places me nearly on the same footing with the south of France. That Mr. Loubat and Mr. N. Longworth, should not have succeeded in the field culture of European varieties, is perfectly natural, and nothing else could be expected, unless they had tried the Rhenish kinds. On the contrary, the fig and almond trees do well with us. This i*, sir, a pretty good index of climate, and it being congenial to them and the cactus, I hold, by parity of reasoning, that the most delicate vines will continue to flourish with us. I am led to suppose, also, that in the same degree as the quince stock, for instance, modifies its graft, so will our luxurious, hardy native vines, affect the European varieties.. Nous verrons.

I wish that such a work as the Ampelogra-phie, by Comte Odart, should be more generally known in this country. Comte de Gasparin, in speaking of this work, in his "Cours d'Agriculture," says.- "We have adopted the nomenclature of Comte Odart, whose Ampe-lographie is the first work which presents, in a manner somewhat general, the character and synonyms of the grape-vines. This work is the fruit of long years of research and experience."

Such are the men I love to imitate, and quote for my authority. With great consideration, Joseph Tog no, M. D. Diccoteaux, near Wilmington, N. C, January, 1851.

P. S. Comte Odart, in his classification of American grape-vines, mentions only three, namely, the Skou-per-nong, (the Indian name, meaning Sweet-water,) the Catawba and Isabella, (Laspeyre) - all three, be it said, en passant, native of North Carolina. This is, at least, a slight proof that this is the region of the grape par excellence.