THE FINE ARTS.--Some months since, an eminent American writer attempted to set forth in these pages the fact that liberty and a republic were no barriers, as had often been alleged, against the progress and perfection of the fine arts in this country; and this position he maintained and supported by triumphant argument. His train of reasoning has since been frequently brought to our minds, by corroborative testimony which has fallen under our own observation; all going to establish the truth, that the enjoyment of a rational freedom, such as we of the United States are blessed with, associated with a general liberal diffusion of property and intelligence, which always carry with them an improvement in taste, is more favorable to the cultivation of the fine arts, than the patronage of kings, princes, and nobles. We were forcibly impressed with the correctness of this assumption, in a recent visit to the studio of the Brothers THOMPSON, whom many of our readers doubtless now hear named for the first time. The elder of the two, C. GIOVANNI THOMPSON, has but recently removed to this city. He has pursued his art with great industry, and his efforts have been marked by gradual yet constant improvement, during a residence of some years in Boston and Providence. His pictures in the Athenæum Gallery, in the former city, won for him a high repute, and brought to his easel several of the first citizens of the New-England capital; and we can speak in terms of high commendation both of the faithfulness and skill with which he has transferred to the canvass many of the élite of the city of Roger Williams. The portrait of President WAYLAND, of Brown University, would be sufficient, were other evidence wanting, of the distinguished talents of the artist, whose success, since his arrival in New-York, has been no less decided. Of his portraits in general, we may say, that they are animated and well-colored, while the attitudes are unconstrained, natural, and agreeable. There is great merit, too, in the pervading tone of his pictures, and especially in the grace, spirit, and expression of his female portraitures.