Miscellaneous . 311 



green colour like that of the same plants exposed in the open air, 

 and even to the sunlight ; those, on the contrary, kept constantly 

 protected from the light of the sun and moon were not at all coloured, 

 and ultimately rotted. More than this : Prof. Giulj ascertained by 

 direct experiment that the light of the moon falling upon certain 

 plants, or certain leaves, has the property of causing the liberation 

 of oxygen (Dei Lavori della Reale Accadem. delle Scienze, 1844). 



I have successfully repeated the experiments of Tessier and Giulj 

 on the power possessed by the rays of the moon in developing the 

 colours of the leaves of plants, and I took the greatest precautions to 

 maintain the pots in all the conditions which were necessary to avoid 

 the objections which might be founded upon the influence of hu- 

 midity or any other atmospheric variation. They were kept in the 

 dark during the whole day ; when the days preceding the full moon 

 arrived, they were carried, after 3 a.m., always to the same place to 

 be exposed to its rays : but two of the pots were uncovered, and two 

 protected from the rays by an opake body ; the others were freely 

 exposed to the open air and all its influence. 



After six nights' exposure, the difference in the coloration was 

 very marked : the little plants constantly protected from the influence 

 of light were white ; and those exposed to the lunar rays had a yel- 

 lowish tint, which appeared to be changing to the green colour. 



I desired to repeat also the experiment of Vassalli. I have only 

 made observations upon leaves perfectly closed, and little shoots, of 

 no vigour, drooping over the edges of the pots wherein they had ger- 

 minated. After that, I tried exposing various specimens of Mimosa 

 pudica to the action of the moon's rays for an hour during full moon. 



1 was delighted to see the little shoots rise after a quarter of an hour's 

 exposure ; the plants were at the distance of a few millimetres from 

 the edge of the pot ; in half an hour the stems were still straighter, 

 and in an hour and a half they had attained the height of more than 



2 inches ; but I could not detect any sensible opening of the leaves. 

 This experiment appeared necessary in order to confirm what has 

 been said of the influence of the rays of the moon upon the growth 

 of the Mimosa, because this fact, more or less established by Vassalli, 

 has not been received with entire confidence by other authors ; and 

 in this last experiment I took the precaution of placing near the 

 Mimosa exposed to the lunar rays another of the same plants covered 

 with an opake body, which shielded it from the light : in this no 

 movement was produced. The experiment was repeated six times 

 with constant results. We may therefore believe that the growth of 

 the little stems of the Mimosa is to be attributed solely to the influ- 

 ence of the moon's rays. 



I made these experiments in the summer of 1847; and I have 

 thought it necessary to enter into details, because I was able to make 

 certain, by a great number of observations, frequently repeated, that 

 the difference of temperature, of the movement of the air, and ex- 

 posures to different degrees of light, had an influence upon the more 

 or less prompt and more or less perfect manner in which the leaves 

 of the Mimosa open and close. 



