Barton, Eaton and Elliott, the works on American birds by Wilson, Bonaparte and Audubon, that on mineralogy by Cleveland--on entomology by Say, and on natural history by Goodman, are highly creditable to the country in which they were produced. Law and medical lectures are frequently published, and law reports are numerous. I believe every State has its reporter, and every year brings forth a volume or two of decisions. Jurisprudence appears to be in this country a more complicated science than in Europe. The student has not only to make himself acquainted with the elements and principles of English law, maritime, civil and criminal, but he has to acquire a knowledge of the laws of the particular state in which he practices, and to know what the courts of the different states have decided, where he does not practice. Law is a favorite science, if indeed it can be called a science, among the Americans. There is scarcely a youth who has received the most ordinary education, that does not undertake to study and practice, or attempt to practice it. In a government of laws like this, law will be a desirable object of attainment, and hence almost every citizen is more or less conversant with the laws by which he is governed. The medical science too, is very extensively cultivated, and this profession has produced several distinguished men, of whom the nation has reason to feel proud. But metaphysical science is almost entirely neglected, which is a matter of surprise when we consider the very inquisitive and refining character of the American mind. Men here, however, have no time for mere abstract speculation; and though many of them refine and subtilize, and split hairs on constitutional questions, they are not very anxious to analyze or investigate mere abstractions, or to attempt to elicit light from the darkness of metaphysical obscurity.--One of the most extensively informed scientific men this country has produced, was Dr. Samuel L. Mitchell of New York, who died during the summer of 1831. He had devoted his life to the cultivation of science, especially the physical sciences, in all of which he was well skilled; but, in consequence of that vanity which sometimes accompanies great attainments, he often became an object of ridicule to his countrymen, who seemed more inclined to depreciate than to exalt his real merits.