Scientific Intelligence. Meteorology. 



could not help it, to the Cicada, which sent forth a note that 

 seemed to leave no cranny unexplored, when I was startled by 

 catching, at a side glance, a brilliant halo of light surrounding 

 the shadow of my head. I turned quickly round to examine it, 

 and found that it proceeded from the moon's light reflected by 

 the dew-drops, clustering thickly on every blade of grass. It 

 appeared to me singularly interesting. I felt continually dis- 

 posed to watch it, and regretted, when I struck into the great 

 road, that it and I had parted company. It seemed to me too, 

 as I walked along, that I occasionally got a glimpse of a much 

 larger and fainter circle, concentric with the other, but this only 

 for a few paces, and it appeared to me plainer when not looked 

 directly at. Since my return to England, I looked, but looked 

 in vain, for this companion of my walk ; there wants the clear 

 brilliancy of tropic moonlight, and the vast copiousness of dew 

 in this less favoured climate. Communication. 



8. Connection between Meteorology and Vegetation. M. 

 Boussingault has addressed a note to the Academle des Sciences 

 of Paris, which is entitled, Comparative examination of the Me- 

 teorological circumstances under which our common grains (the 

 Cerealla)) Turkey-wheat (Maize), and potatoes, vegetate at the 

 Equator, and In the Temperate Zone. In this examination the 

 author has first made investigations into the time which elapses 

 between the first springing of the plant and its full maturity. 

 He then determined the temperature of the space of time which 

 separates these two extreme epochs of vegetable life. By com- 

 paring these data concerning any given plant which is cul- 

 tivated both in Europe and America, he arrives at this curious 

 result : That the number of days that separates the commence- 

 ment of vegetation from its maturity, is more considerable in 

 proportion as the mean temperature, under the influence of which 

 the plant grows, is less ; the duration of the vegetation will be 

 equal, however different the climate may be, if this temperature 

 is identical in the two places ; and it will be shorter or longer 

 according as the mean heat of the period of time necessary for 

 the accomplishment of the vegetation, is itself greater or less ; 

 in other words, the duration of the vegetation appears to be in 

 the inverse ratio of* the mean temperatures. So that if you 

 multiply the number of days during which any given plant vc- 

 gvtatcs in these distinct climates, by the mean temperature of 



