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the one that remained in the shade, the same upon which the observation at the mountain had been made, was not in fact higher than 103, though marked in the table of observations at 107 (91).
99. But the difference between the observations made upon the mountain of Sixt, and those I am speaking of, was still greater by much after sunset The 30th of August, at a quarter after ten at night, I observed the hygrometer without side the cottage upon the mountain, and found it at 123 (79) ; and on the 11th of September following. in the plain, it was not higher than 31 at 9, and 24 at 10 o'clock. The wind was south, and the height of the barometer upon the plain, pretty much the same during both the observations.
100. It is true that, notwithstanding the similarity of these circumstances these observations cannot be directly compared, on account of the disagreement in some other circumstances. In the first place, the difference of fourteen days at this season of the year may have produced a sensible change in the state of the air. There was already, for instance, a considerable difference in the degrees of the thermometer; it was at 13 and 3/4 when the observation was made on the mountain, and no higher than at 10 on the plain. Besides, at this time of night, there would always be an essential difference between the upper and lower parts of the atmosphere, even though in the day time they should have the same degree of humidity for the vapours being condensed after sun-set, and thus producing a kind of dew, they must necessarily descend, and from this very cause be more abundant io the low grounds than
