I was pleased to see the question raised concerning the White Muscat of Alexandria, in your last number, (page 08.) I hope some of your correspondents who hare had a long and satisfactory experience, will answer it. In the meantime, I will tell what I know on the subject. I have a few of the foreign varieties of the grape, planted three years ago; and last year I enlarged the house, and set out more. Among the oldest is one White Muscat of Alexandria, bought of Parsons & Co. Last summer it bore, for the first time, four clusters of beautiful grapes. I had formerly been doubtful of the success of this kind, especially as Mr. Downing has said "that it will scarcely attain its highest flavor without fire heat." As it started later than the Hamburg and Chasselas, some old sash were laid on the outside border, which caused it to operate like a hot-bed. This precaution had a decided influence in accelerating the flow of the sap. The house was kept as close and warm as possible, by which means the temperature of the roots in the outside and inside border was rendered equable.

This I think to be an important consideration, and Professor Lindley makes the same suggestion, in his Theory of Horticulture. On some of the hottest days in July and August, I would remove the sash in day time, but return it at evening, and so prevent an undue radiation of heat during the night; but ordinarily kept it on night and day, except in the season of rain. The heated air, well saturated with moisture, directly under the glass is very grateful to the roots; and by this process they are constantly attracted towards the surface, where they find plenty of air and aliment. My Royal Muscadine were ripe in the middle of August, the Black Hamburg about the 10th of September, and the White Muscat of Alexandria the 1st of October. The latter were large-sized berries, transparent, greenish white at first, and becoming yellowish at maturity. They had also that musky and delicious flavor, which is a sure evidence that they had been grown in such a temperature as is suited to their nature. Whether this variety is best of all, is still an open question, and will be, so long as different persons have different tastes. Its good qualities are its solidity and crispness, but melting at the same time, and its high musky flavor.

The skin is rather thin, the seeds are few, the color delicate, and the shape oval. The only disadvantage is that it requires a high temperature, and is more liable to fail in a cold season. It is however objected to by some, on account of its perfect sweetness, being thus more cloying to the appetite than other grapes. I think, myself, if I were shut up to one variety, I should (all things considered,) choose the Black Hamburg, and next the White Muscat. What is called the "Black Barbarossa," I have never seen. If the White Muscat is so popular with the English, it is because they are grown in forcing houses, and the border enclosed within. Their climate forbids any other supposition.