300 EFFECT OF FORESTS UPON HAIL-STORMS. 



stopped or turned aside by the presence of a forest of considerable size. 

 He had taken for his data the hail-storms that had fallen durin;; the last 

 thirty years, in a commune where registered by insurance companies 

 with the greatest care, and which, with other records, enabled him to 

 construct charts on a uniform model, and very completely. A small or 

 isolated forest did not have this effect. 



In the department of Eure-et-Loire, the forest of Senouches had 

 proved a protection to a part of the canton of Brezolles. In the north 

 of the department, the storms followed the valley of the Eure until, 

 meeting the forest of Dreus, the storms divided into two parts. In 

 Loiret, on the right bank, the storms meeting the vast forest of Orleans, 

 separate into two parts; one follows the Loire until near the forest of 

 Lorris, which it penetrates by a depression, and seems to wish to unite 

 again with the upper branch, which it sometimes does, but oftener the 

 forest of Montargis prolongs the effect of the forest of Orleans, and 

 keeps the zones separate. The further effects of forests are shown by 

 charts, proving that great woodlands divide and considerably weaken 

 the force of these storms. The branches of the trees are so many light- 

 ning-rods, conveying to the ground the electricity of the atmosphere, and 

 neutralize this agency as well as the hail. The forest of Orleans, along 

 the divide of the Loire and the Seine, produces an effect at once clear 

 and decisive. According to Becquerel, the common saying of the coun- 

 try is, that a hail-storm never strikes the forest. 



M. Sainjon, engineer, president of the meteorological commission of 

 Loiret, in a further study since published, has conlirmed by a series of 

 remarkable tacts the observations previously made. 



The memoir of M. Bailie in a multitude of places presents from records, 

 proving this effect as uniformly seen wherever forests occur of sufficient 

 size to produce these results. These researches are continued in subse- 

 quent volumes of the Atlas Meteorologique, under tlie editorial care of 

 the astronomer Le Verrier, with continually-recurring evidences of 

 these factSj and illustrations of their effect in series of charts. 



EFFECT OF COLOEED LIGHT UPON VEGETABLE GROWTH. 



On the 18th of December, 1871, M. Bert reported to the French 

 Academy of Sciences the result of experiments under the influence of 

 colored light. Twenty-five species of growing plants, belonging to as 

 many families, were exposed to the same conditions, under colored 

 glass, not receiving the direct light of the sun. The conclusions of his 

 experiments were : 



1. That green is almost as destructive as total darkness. 



2. That red is very injurious, but uot so much so as green, and that it causes plants 

 to elongate in a singular manner. 



3. That yellow is less injurious than the above, but more so than blue. 



4. That any one of the colors has a bad effect on plants, and that their union in the 

 proportion that forms v,'hite light is necessary to vegetable health. 



The light that traverses a leaf, when examined by a spectroscojie, sho-ws an abun- 

 dance of green and red rays, which are not utilized bj the plant. It is not, therefore, 

 ■wonderful that young trees will uot spring up in the dense shade of the parent tree. 

 But trees differ somewhat in the quality of the light that is absorbed and transmitted, 

 and the mosses and liverworts that enjoy the red rays, will therefore thrive luxuriantly 

 in the densest forest shade. It is highly probable that the reason why the beech will 

 grow under the shade of oak better than the young oak itself, may bo due to the fact 

 that some of the rajs transmitted by the leaves of the oak are appropriated by the 

 beech.i 



'An interesting observation was made in 1792 by Chancellor Livingston, ot ^ew 

 York, with respect to the influence of shade upon vegetation and the differences shown 

 by trees in this respect. He plantedi a field of corn on the west side of a young wood, 



