Observations bearing on the second of the three points have been made by Becquerel in France, by La Cour in Jutland and Iceland, and by Rivoli at Posen. The results are perfectly congruous. Becquerel's observations[51] were made under wood, and about a hundred yards outside in open ground, at three stations in the district of Montargis, Loiret. There was a difference of more than one degree Fahrenheit between the mean annual temperatures in favour of the open ground. The mean summer temperature in the wood was from two to three degrees lower than the mean summer temperature outside. The mean maxima in the wood were also lower than those without by a little more than two degrees. Herr La Cour[52] found the daily range consistently smaller inside the wood than outside. As far as regards the mean winter temperatures, there is an excess in favour of the forest, but so trifling in amount as to be unworthy of much consideration. Libri found that the minimum winter temperatures were not sensibly lower at Florence, after the Apennines had been denuded of forest, than they had been before.[53] The disheartening contradictoriness of his observations on this subject led Herr Rivoli to the following ingenious and satisfactory comparison.[54] Arranging his results according to the wind that blew on the day of observation, he set against each other the variation of the temperature under wood from that without, and the variation of the temperature of the wind from the local mean for the month:-- +-------------------------------------------------------------+ | Wind. | N. | N.E.| E. | S.E.| S. | S.W.| W. | N.W.| | |-----+-----+-----+-----+-----+-----+-----+-----| |Var. in Wood |+0.60|+0.26|+0.26|+0.04|-0.04|-0.20|+0.16|+0.07| |Var. in Wind |-0.30|-2.60|-3.30|-1.20|+1.00|+1.30|+1.00|+1.00| +-------------------------------------------------------------+