Dear Sir: As the permanent improvement of the native grapes by hybridization with the exotics, is a matter of much national importance, you will perhaps, excuse me for requesting again a corner in your valuable Journal, in answer to the caustic remarks of Dr. Valk.

As I am apt, upon honest conviction, to speak somewhat abruptly, I committed the same error by saying, " he has gone the wrong way to work." That some polite effusion of language might have been used to express the same meaning, without giving offence, I admit, and hope he will excuse the expression; but it is not by indulging in invective and braggado-cia, nor yet by applying sarcastic pique against a triflng misplaced etiquette, that science and observation are to be put down.

As the matter at present stands, in this instance, your correspondent has proved little more hi his favor than positive assertion founded upon presumptive evidence, - and his assumed position is a wrong inference, for he is surely aware that the desideratum is not so much the hardiness, as to standing the severe frosts of winter, but a constitutional power to resist mildew during the growing season: and though the former is a very desirable point, yet it is a trifling matter compared with the latter. We know that in many situations far north of this neighborhood, the foreign grapevine will stand unprotected without injury; and if they did not do so, we might cover them with earth, as is done with the Fig and the vinein the vineyards in the steppes of Russia. I sincerely hope that he has gained all that he asserts, but under the circumstances it yet remains to be proved, whether or no be has got a true cross, for it may yet turn out to be nothing more than an inferior variety direct from the Hamburgh, as I know that seedlings from that variety often answer the description of your correspondent j and those " who know" will look with skepticism, at least, upon the experiment, until it has been grown in different localities, and under various circumstances.

And I repeat that he would have made surer work of it, as regards constitution, and most likely fruit, also, if the Isabella had been crossed with the Hamburgh. Although " practical experience" may some* times prove my argument to be incorrect, Dr. Valk has not yet shown it to be so - and if he will give it a fair and unprejudiced further in* vestigation, and as fairly submit his experience thereon to public decision, I will willingly abide by the verdict. If, acting in accordance with the inscrutable and immutable laws of the all wise designer of the universe, is, In his estimation, catering a'la Barnum, he is welcome to the delusion. What I stated is founded upon the results of many experiments upon dine* rent tribes of plants; it is a demonstrated fact, and is supported by the authority of the most scientific investigators of nature.

I do not wish to be a disputant, nor to detract from the honor due to your correspondent, and I hope that he will receive these comments with as good feeling as they are penned. Ify desire was to throw a mite into the treasusy of useful knowledge, for the benefit of others, and if it should hereafter realize my wishes, I care not for his severe, but futile remarks. I am yours most respectfully. WM. Chorlton. Afao-Brighton, Staten Island, July 15,1852.