Page:Scientific Memoirs, Vol. 2 (1841).djvu/76

64, although, in the mean numbers for the single months, in the fourth and eighth columns, ten months give a difference in the same direction.

By combining the forenoon and afternoon fluctuations we obtain the following means:

Mean Values.

According to the numbers of the fourth column somewhat greater fluctuations occur in the months from July to December than in the other six; but the mean values 3′ 33″ and 3′ 1″ have too small a difference to justify a conclusion that greater fluctuations commonly prevail in that period of the year, especially as the difference has been principally occasioned by an excess in the single year 1835–1836.

On the other hand, the inequality of the fluctuations in each of the three years, in relation to one another, is very perceptible; the mean value for the third year being about half as large again as that of the first year. The general mean, from all observations hitherto made, 3′ 18″, might therefore be considerably changed by a longer continuance of the observations.

These are the results which may be drawn from the daily register kept hitherto. It is highly desirable that similar observations should be made at several stations, and at some they have recently commenced. If, as is done at Milan, the observations