This excess of magnetic intensity and electricity not only gives a peculiar character to our vegetation, but also to our race, our animals, and every thing. He who supposes that the restless activity and energy of the people of the United States is the result of habit, or education, or any fortuitous circumstances alone, is mistaken. Let him watch the contrast in his own feelings during those occasional languid, damp, and sultry, although not thermometrically, hot days--which so much resemble the summer weather of England--with those days of bright, bracing, N. W. and S. W. air, so much more frequent here, and he will appreciate the difference. That term "bracing," so much in use, will express the effect of this peculiar weather. It "girds up the loins," both of body and mind. Men and animals can work with more ease, even in our peculiar extremes of heat, than they can in England, and fatten with less. A similar difference in degree is found between our climate and that of the Pacific portion of our country. Something is due to the difference in the volume and moisture of the counter-trades, and something to the contiguity of the Pacific Ocean; but to the difference in magneto-electric intensity, the contrast is mainly due. Corn and cotton will be grown, to some extent, in the valleys west of the meridian of 105 deg., but never as successfully as east of it. The aurora is periodical, like all the other atmospheric phenomena, but its periodicity is not accurately ascertained. It is believed to have occurred much oftener during the second quarter of this century, than during the first. It is known, however, to occur most frequently in the spring and fall; and during those periods when the active and rapid transit of the atmospheric machinery produces the greatest degree of magnetic disturbance. This identifies it with terrestrial magnetism. Dalton gives us the following table of observations, arranged according to the months when they were seen. Jan. Feb. Mar. Apr. May. June. July. Aug. Sept. Oct. Nov. Dec. (1) 18 18 26 32 21 5 2 21 23 36 38 9 (2) 21 18 23 13 3 2 1 3 35 22 22 21 (3) 21 27 22 12 1 5 7 9 34 50 26 15 (4) 5 6 4 8 10 7 6 14 14 17 5 6 (1) contains those observed by him at Kendall; (2) are taken from another list; (3) is MARIAN'S list of those observed before 1732; and (4), those seen in the State of New York in 1828 and 1830. Mr. Stevenson's table of those observed by him at Dunse, from 1838 to 1847, inclusive, is as follows: Jan. Feb. Mar. Apr. May. June. July. Aug. Sept. Oct. Nov. Dec. 32 20 18 18 3 0 2 14 43 34 30 23