It is an error that our climate is more variable, or the summers materially hotter, than in a correspondent latitude in the Atlantic states. "The New Englander and New Yorker north of the mountains of West Point, should bear in mind that his migration is not to the _West_ but _South West_; and as necessarily brings him into a warmer climate, as when he seeks the shores of the Delaware, Potomac, or James' River."
The settlers from Virginia to Kentucky, or those from Maryland and Pennsylvania to Ohio, or further west, have never complained of hotter summers than they had found in the land from whence they came.
To institute a comparative estimate of temperature between the east and the west, we must observe: first, the thermometer; and, secondly, the flowering of trees, the putting forth of vegetation, and the ripening of fruits and grain in _correspondent latitudes_. This has not usually been done. Philadelphia and Cincinnati approach nearer to the same parallel, than any other places where such observations have been made. Cincinnati, however, is about 50' south of Philadelphia. The following remarks are from Dr. Daniel Drake of Cincinnati, to whose pen the west is much indebted.
"From a series of daily observations in Cincinnati or its vicinity, for eight consecutive years, the mean annual temperature has been ascertained to be 54 degrees and a quarter. Dr. Rush states the mean temperature of Philadelphia at 52 degrees and a half; Dr. Coxe, from six years' observations, at 54° and a sixth; and Mr. Legaux, from seventeen years' observations, at Spring Mill, a few miles out of the city, at 53° and a third; the mean term of which results, 53° and a third, is but the fraction of a degree lower than the mean heat of Cincinnati, and actually less than should be afforded by the difference of latitude.
"A reference to the temperatures of summer and winter, will give nearly the same results. From nine years' observations, (three at Spring Mill, by Mr. Legaux, and six in Philadelphia, by Dr. Coxe,) the mean summer heat of that part of Pennsylvania, appears to be 76 degrees and six-tenths. The mean summer heat at Cincinnati, for an equal number of years, was 74 degrees and four-tenths. The average number of days in which the thermometer rose to 90 degrees or upwards, during the same period, was fourteen each summer; and the greatest elevation observed was 98 degrees: all of which would bear an almost exact comparison with similar observations in Pennsylvania. Mr. Legaux states the most intense cold, at Spring Mill, from 1787 to 1806, to have been 17 and five-tenths degrees below cipher,--while within the same period it was 18° at Cincinnati. The average of extreme cold for several years, as observed by Mr. Legaux, was one and eight-tenths of a degree below cipher:--the same average at Cincinnati, was two degrees below. From all which we may conclude, that the banks of the Delaware and Ohio, in the same latitudes, have nearly the same temperature."