1885.] METEOROLOGY. 379 



July and August from the variations of teuiperature obtained for 

 the same period in the open field. The disfoliaged forest, on the 

 other hand, showed hardly any sign of having affected the variations 

 of temperature. The maxima, as also the minima, of temperatures 

 were likewise calculated by the month for the different stations, and 

 from the data thus obtained the annual curve was drawn. For 

 the open field the curves of the maximum and of the minimum 

 temperatures showed a pretty similar course, the maximum of both 

 occurring in summer, and the rise and fall of the curves being 

 likewise tolerably uniform. For the forest station the curves of 

 the maximum and of the minimum temperatures were different. 

 The maximum curve lay, on the whole, lower than the corresponding 

 curve of the open field. It moreover attained its utmost height 

 in May, resting there, with but slight changes, throughout the 

 summer. In autumn the curve sank, reaching, in winter, quantities 

 not essentially different from those of the field curve. The curve 

 of minimum temperatures, on the other haud, in the case of the 

 forest station, showed higher values than obtained in the case of 

 the free station. In the pine forest the course of the minimum 

 curve came nearer to that of the field curve, and there, too, a 

 maximum was found in summer. In the beech forest, however, 

 the curve attained its maximum as early as May, keeping that 

 level pretty nearly all through the summer, but sinking more 

 rapidly in autumn, and descending lower than did the curve of 

 the pine-forest station. As a result of his investigation. Prof. 

 Miittrich had arrived at certain definite conclusions respecting the 

 influence of the forest on temperature, which may be stated as 

 follows : — (1) The forest exercised a positive influence on the tem- 

 perature of the air; (2) the daily variations of temperature were 

 lessened by the forest, and in summer more than in winter ; (3) 

 the influence of the leafy forest was in summer greater than that 

 of the pine forest, while in winter the tempering influence of the 

 pine forest preponderated over that of the disfoliaged forest. An 

 attempt to determine the influence of the forest on the mean 

 annual temperature led to no sure results. — Nature. 



ON TEMPERATURE AND WOOD-GROWTH IN 

 DECIDUOUS AND EVERGREEN TREES. 



THE enthusiasm and energy with which the late Sir Eobert 

 Christison, in his vigorous old age, applied the methods of 

 skilled diagnosis, acquired in practice as a consulting physician, to 

 the question of tree-growth, must be still remembered by those of 



