121 . Phenomenon manifested in the Suyar-Cune. 



evolved in warm climates, where storms are jo frequent and 

 so frightful. 



During the rain-storms occurring in the Savane, the same 

 effect must obviously take place by the great quantity of 

 the electric fluid which, meeting in its passage with ammo- 

 niacal gas disengaged from the soil so rich in azotised mat- 

 ter, must have produced a notable proportion of nitric acid, 

 which descended with the rain and passed upon the leaves 

 of the cane; and under the influence of the high tempera- 

 ture and the light, scorched them, leaving after it those 

 yellow longitudinal marks which give the leaves a ribbon- 

 like appearance. 



To produce a similar effect, I mixed one drop of common 

 nitric acid with 200 drops of water allowing the mixture to 

 fall drop by drop from a capillary tube unpon Cane-leaves 

 placed ia an oblique position ; in the 9pace of 2i hours after, 

 wherever the liquid had glided drown, it left the same trace 

 of colours as those I had observed in field of canes, that is, 

 a whitish tint which turned yellow when brought into 

 contact with the luminous rays. 



It is easy to understand that the action of such acid so 

 mixed with the rain-water would do but little mischief to 

 the cane itself, merely scorching portions of the leaves; 

 but it might have been otherwise mischievous, if the rain- 

 drop impregnated with this acid, after having glided over 

 the leaves, had united themseves at the upper part, that is, 

 at the heart of the cane, whence the acid would have had 

 no means of escape; this portion of the plant in which the 

 leaves are still tender offers a larger scope for the delete- 

 rious action of the liquid; I have consequently remarked 

 the young leaves which surround the flower, wrinkled in a 

 state of destruction, and being unablo to offer any protect- 



