Thus, it is believed that many, perhaps all of the alternating terms of heat and cold, are dependent on magnetic waves passing over the country in a similar manner, with a greater or less belt of condensation between them, and depending on peculiar magnetic action traveling in the same way. The S. E. extension of showers and storms, and the cooler changes of temperature which immediately follow them; with light N. W. wind in mid-summer, and with it fresher at earlier and later periods, in the form of northers blowing violently, according to the season, are intimately connected, and indicate such waves. The indication is strengthened also by the frequent progress of auroras in like manner, occurring usually after the belt of condensation has passed, and frequently following it. The clouds and currents of the atmosphere, so far as I have been able to discover, show no permanent current from the pole to the atmospheric equator, compensating for the counter-trade; and that compensation is furnished by the periodical but frequent atmospheric waves, connected with the periodical changes of storm, and cloud, and sunshine, which gradually extend from north to south, in or near the magnetic meridian. Perhaps such compensating currents are found west of the magnetic poles, as we have suggested, and make the N. E. and northerly dry winds of Western Europe and the Pacific; but, in the present state of our knowledge, it is impossible to say that they are. If it be so, the compensation they furnish must be small; for the volume of counter-trade which is not depolarized before it reaches the Arctic circle, and which passes round the magnetic pole, must be very small. A majority of our periodical changes, during the northern transit, and I believe at all seasons, are of this character; and, I have reason to believe, from observation, in one or two cases, that where belts of rains and showers begin, over _any locality_ in the United States, they may assume this character. I have been in Saratoga when an easterly storm commenced _south of that place_; the condensation and mackerel sky being visible at the south, and no cloud formation or rain occurring there at the time, and have traced it afterward as a belt which had a lateral extension south-eastward. Leaving that place immediately after a belt had passed south, I have overtaken it by railroad, and run into it again before arriving at New York; and witnessed its subsequent extension south-eastwardly, out over the Atlantic. I have witnessed the approach of such a belt in the spring, at Sandusky, upon Lake Erie, and its passage over to the S. E., followed by the N. W. wind, as Mr. Bassnett describes them at Ottawa, and run under the attenuated edge of the same belt, on the same day, on the way to Pittsburg, leaving the N. W. wind behind, but finding it present again with clear sky on the following morning. I have seen hundreds of them approach from the north, and pass to S. E., out over the Atlantic;