518 THE UNIVERSE. 



CHAPTER IV. 



DENSITY OF PLANTS. 



As the duration of life in trees presents such vastly op- 

 posite limits, we expect to meet equally enormous differ- 

 ences in their density ; and this is the case. 



Those singular plants, the Tremella3, which, after a wet 

 night, or even merely a storm, suddenly bestrew the earth 

 in the shape of so many tremulous masses of jelly, covering 

 the ground where a few hours before there was not a ves- 

 tige, and which, on account of the unexpected manner in 

 which they appear, were looked upon by the alchemists as 

 a supernatural production, an emanation from the stars, are 

 so soft that the least pressure crushes and reduces them to 

 water. 



In the same class to which these gelatinous plants belong 

 we find others of a surprising degree of firmness. This is 

 the case with certain Alga3 scattered over the shores of Asia, 

 and in particular with the Fucus tendo, the toughness of 

 which has been compared to that of the tendons which con- 

 vey movement to the limbs of animals. In appearance this 

 marine plant is exactly like a cord, and as it possesses the 

 strength of cordage the Chinese, who are so ingenious in 

 everything, make use of it in order to tie up bales of goods. 

 In Japan this fucus serves for making fishermen's nets. 



In some trees of considerable size the trunk is scarcely 

 harder than in these plants : for instance, that of the Bom- 

 bax ceiba, or cheese-plant, is as soft as the article of food 

 after which it is named. 



