The Boston Transcript gives so intelligible an account of Mr. Simpson's mode of obtaining three crops of grapes in two years, that we copy it for the information of our readers.

"Mr. Simpson states, as the foundation of his theory, the following principles: -

1. To perfectly ripen the wood, leaf, and bud.

2. To secure a thorough resting of the vine, by withholding moisture from the roots; and;

3. To keep up a brisk root action throughout the growth of the crop.

By imitating the dry season of tropical countries, he effects the ripening of the wood, and the fall of the leaves of the vines that have produced his early spring crop, and the vines are then laid down to rest until the period of three or four months, the season of rest shall have passed, when they are again set up, and encouraged to bearing.

It is obvious that his vines that bore his late crop, say in September, ripen their fruit, and their wood, and let fall their leaves through the influence of autumnal cold.

His chief improvement appears to be in applying drought as a substitute for the cold of winter, and in managing to have his vines in bearing every eight months, so as to produce three crops of grapes in two years. This gain he effects without any injury to his vines, as sufficient practical trials have already proved.

With regard to the method of cultivation of these vines; ten days before starting the buds, the earth is warmed, and in three weeks the vines are ready to be set up. They were started on the 15th of December, 1854, and bloomed in five weeks. The first swell of grapes was four weeks after blooming; four weeks later, the seeds are hardened, and, during this most important vital process of the plant, there seems to be a suspension of growth of the juicy portion of the fruit. In four weeks more the grapes ripen. In all, the time is about sixteen weeks. On the 20th inst., the early grapes - 'Macready's Early 'White' - had been ripe for some time, and the Black Hamburgh, Chasselas, and other late varieties, were nearly ripe - some of the bunches being quite perfect and of high flavor.

The vines, now loaded with ripe grapes, will be laid down to rest, and not be again awakened until next August, when they will be set up for their next crop, which will be ripe in January.

They will next be started in April, and will ripen in September following, and then again they will be started in December. Thus the three crops will be produced in twenty-four months, or eight months for each crop".