summer of Knoxville to be from one to two degrees cooler than that of Glenwood. The summer mean of Knoxville is, doubtless, nearer 73°.6, at which it was placed in Dr. Safford's report. Assuming this to be correct, Knoxville has about the summer temperature of Philadelphia, Penn., as well as that of several points in Central Virginia, of Cincinnati, Louisville, Ky., Southern Indiana, and Central Illinois. It is, too, that of the central part of Spain and the northern part of Italy. The summer of the East Tennessee Valley is, therefore, considering its valley-like character and its low latitude, a comparatively cool one. This is mostly due to the considerable elevation of the region above the sea.

This lower summer temperature has its influence in giving to East Tennessee agricultural features, to some extent, different from those found elsewhere in the State.

It might be thought that the mountain ranges which bound the Valley on both sides would materially affect its climate. This, however, is not the case. These ranges are happily so situated as not to obstruct, to any considerable extent, the southwesterly and westerly winds, which of all others, in an agricultural point of view, are most important. The great trough, of which the Valley is a part, is open towards the southwest, so that these winds, coming from the Gulf of Mexico, and charged with warmth and moisture, flow freely through it, imparting, during the spring and summer, fertility to all its parts. The mountain ranges, doubtless, change the direction of the winds to some extent, and thus make southwesterly and northeasterly winds more frequent than they would be otherwise.

The summer of the Central Basin, the mean of which for the middle part may be placed at 75°, but ranging from about 74° to 76° in passing from the northern to the southern portions, is approximately the same as that of the northern parts of Georgia and South Carolina.

West Tennessee has summer means higher by about a degree than those of the Central Basin. The differences are sufficient to lengthen the growing season, and so to modify the climate as to throw a large part of this division into the cotton-growing region.

The average winter temperature of the middle parallel of the State may be placed at about 38°, and it is doubtless nearly the same in East, Middle and West Tennessee.

From the Glenwood table (No. 3) it is seen that January is the coldest month, 34°.08 being the mean of this month for 21 years; then follows December, its mean being 38°.54; then February, 41°; and

then the remaining months in order as follows: November, 46°.45; March, 47°.30; October, 57°.17; April, 57°.84; May, 64°.98; September, 69°; June, 72°.14; August, 74°.85; July, 76°.22, which, as the hottest month, terminates the climax.

The temperature of the Cumberland Table Land is from four to five degrees lower than that of points on the same parallel in the Central Basin, and from two to three lower than corresponding points in the Valley of East Tennessee. The difference in temperature is most apparent at night., The Table Land has been for years a favorite resort during the hot months. Scores of summer retreats, public and private, may be found upon its flat tops, most of them located on or not far back from its cliff-bound edge. At several points, as at Beersheba and Lookout, summer hotels have been erected, and these have clustered around them many elegant cottages, altogether forming attractive mountain villages. This has been brought about by the agreeable summer temperature and the pure air of the Table Land, in connection with its pleasing and, in the vicinity of its escarpments, its wild and grand topographical features.

During the summer of the year 1859, Benj. Bentley, Esq., of Spring Grove, upon the Table Land in Cumberland county, and Prof. A. H. Buchanan, of Cumberland University, Lebanon, made regular and systematic observations, at their respective residences, in order to furnish data for the comparison of the mean temperatures of the two places. The following tables contain the results:

No. 5.-Mean Temperatures for the Summer of 1859, at Spring Grove,
Cumberland County, Tenn.

No. 6.-Mean Temperature for the Summer of 1859, at Lebanon, Wil

No. 7.-Extremes of Temperatures, or the Maxima and Minima, observed

during Summer.

According to the first two tables, the summer mean at Spring Grove is 4.24 degrees less than at Lebanon. The former has, however, a lower latitude than the latter. Correcting for this, or supposing the points to be on the same parallel, the difference in temperature becomes greater, and is equal to about 4.5 degrees. Observations taken at Nashville during the same summer show very nearly the same result. The highest ridges of the Unakas have a mean yearly temperature of about 42°, which is that of the northern shore of Lake Superior and of Quebec and Montreal. This will account for the presence of trees and other plants on these mountains belonging to a Canadian flora.

2d. Extreme Temperatures. The following table, No. 8, prepared by Prof. W. M. Stewart, from his observations taken at Glenwood, is full of interest from an agricultural point of view. It shows the vicissitudes of temperature to which vegetation is exposed-an important consideration. It is, also, highly interesting in other respects, which will be appreciated by the intelligent reader.

In the following table the minus sign (—) indicates temperatures below zero. The thermometers employed in these observations are of the most careful construction, are provided with adjusting arrangements at the top of the tube, and are at least verified once during the year by reference to the freezing point. They are free from reflected heat, and exposed to an open circulation of air, on a northern aspect.

It will be observed, by an inspection of the table, that during the period over which these observations extend, the temperature has never reached 100° Fahrenheit during the warmest terms, a temperature which is frequently attained in the Northern States and Canada. In July, 1860, the mercury rose to 99°, which is the highest range. During the same period, it will appear, the temperature has fallen below zero on several occasions, the lowest being minus 8°, in January, 1857 and 1864, respectively, making the range for the period, 107°. Our coldest days occur in January; the warmest in July, with very few exceptions.

The average of the extreme low temperatures of the years in the above table is 2°.6. In but six out of the twenty-two years was the thermometer below zero. Uniting the lowest temperature of December, 1872, as given in this table, with the lowest of January and February in tables Nos. 1 and 2, it is seen that the thermometer did not fall to zero during the winter of 1872-3, which was so remarkable for its extreme cold at the north.

It may be added here, that in general, a median line drawn east and west through the State is the limit of domestic ice-houses. South of this the ice season is too uncertain to justify the expense or trouble in constructing them. North of the line, about once in seven years there is a failure in the ice crop. On the north side of the Highland Rim the ice, probably once in ten years, attains a thickness of six or seven inches; in the Central Basin it very rarely attains a thickness of four inches. The most usual thickness, however, of both regions is from two to three inches.

3d. Period between Killing Frosts. The length of the growing season is measured, to a great extent, by the period between killing frosts. This is, therefore, an important element of climate. Here again we are indebted to the extremely useful labors of Prof. Stewart.