The Botanic Garden of the late Mr. Swainson at Twickenham.- We first visited this garden in April, 1804, during the lifetime (if we are accurate in our recollection) of the late Mr. Swainson, a good practical botanist, and much attached to gardening. Every thing, we recollect, was then in the very highest order and keeping, under the care of Mr. Arthur Biggs, now of the botanic garden, Cambridge. The general impression on our minds, for the last fifteen years, has been, that this garden, as such, no longer existed; but we were agreeably surprised to learn that we were mistaken, when attending the meeting (noticed p. 463.) which was held, on July 18., to arrange a plan for forming a Metropolitan Botanic Garden, by the present gardener, Mr. Castles, coming forward, and voluntarily offering a donation of 500 species. Mr. Castles did not succeed to the management of this garden till some years after Mr. Biggs left it. He found that Mr. Biggs's immediate successor had taken the shortest method of managing the place, viz., pruning the arboretum by clipping all the trees and shrubs to round heads; allowing the more tender herbaceous plants to die off without renewing them, and those that remained, to cover the surface in a natural manner. The hot-house, which, in Mr. Biggs's time, was filled with the most choice tropical plants of that day, was turned into a vinery, as was also the large green-house; and the smaller hot-houses and pits were neglected, or used for raising early cucumbers and potatoes for sale. Mr. Castles, having been known to the late Mr. Swainson, was allowed by his widow a certain licence as to restoration; and the very existence of the place as a botanic garden may be said to be entirely owing to his enthusiasm. He is allowed a very inadequate sum for keeping the whole in order, and the privilege of selling plants. The latter privilege amounts to next to nothing in a pecuniary point of view; but it enables Mr. Castles to make exchanges with other botanic gardens; and thus, in some degree, to keep up the character of the place. All the circumstances considered, he has the highest merit; and we hardly know any one but himself, who, with such slender means, could maintain so respectable an appearance, and who could bear up so well against an increasing pressure of difficulties.