_Jeffersonville, (Indiana,) October 16, 1819._ To determine the most proper parts of America for new settlers, is a proposition interesting in its nature, but one that cannot be solved with precision. This general fact is to be kept in view, that, in the old populous settlements, land is already too dear to admit of that spontaneous increase in value so profitable in back-wood districts. The sea-board then is to be rejected by those who would go in search of the most profitable investment of their capital, and some part of the interior country is to be selected. The vast migration from the eastern States to the western, is satisfactory evidence of this state of the land market; and, besides, countenances the opinion, that the country first peopled by Europeans is not destined to such population and wealth as that rationally anticipated in the more fertile western States. In the most inland parts of the old States, there are still abundance of good woodlands reserved for future cultivation, embracing an extensive range of climate, and a great diversity of vegetable products; but the natives of the temperate climes {157} of Europe will, for the most part, be averse to live under the scorching sun of Georgia, or the intense frosts of the province of Maine. Somewhere between the extremes, probably between Hudson River and Chesapeake Bay, affords the best approximation. At Philadelphia, for example, the mean temperature of the year may be stated at 53.66°, that quantity being a mean of the results obtained by the observations of Dr. Rush, Dr. Cox,[86] and Mr. Legoux;--a determination nearly coinciding with that of Mr. Playfair,[87] (53.58°) for the mean temperature of the vegetative season, from the 20th of March to the 20th of October, at Edinburgh, and only 5.86° higher than the mean temperature of the latter place for the whole year. It is true that the extreme variations are much greater at Philadelphia than at Edinburgh, but it will be in vain to search for a situation in the United States, possessing that equability of heat, that characterizes the British islands.