50 



does not take place in all the leaves of one 

 plant, or one branch at a time; but is appa- 

 rently devoid of uniformity, regularity, and 

 sympathy. It is likewise independent of all ex- 

 ternal stimulation, except that it requires a 

 warm, close, and quiet atmosphere. Young 

 plants exhibit these phenomena the best, and 

 they do not require the presence of the sun's 

 light. The writer of the article in Dr. Rees's 

 Cyclopedia, says, " We have never seen it in so 

 much perfection as by candle-light, in a very 

 warm close apartment." And it is observed by 

 the younger Linnreus, that it loves shade and 

 rainy weather, and performs its movements very 

 well during the night. 



MECHANICAL WONDERS OF A FEATHER. 



Every feather is a mechanical wonder. If we 

 look at a quill we find properties not easily 

 brought together, strength and lightness. I 

 know few things (observes Dr. Paley) more re- 

 markable than the strength and lightness of the 

 very pen with which I am writing. If we cast 

 our eye to the upper part of the stem, we see a 

 material, made for the purpose, used in no other 



