■)Oli THE UNIVERSE. 



In the same class to which these gelatinous plants 

 belong, Ave find others of a surprising degree of firmness. 

 This is the case Avith certain Algai scattered over the 



271. The AVarty Nostoc — TremcUa mescnterica. 



shores of Asia, and in particular with the Fticiis tendo, 

 the toughness of Avhicli has been compared to that of 

 the tendons which convey moA^ement 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 Bomhax 

 Ceiha, or cheese-plant, is as soft as the article of food after 

 Avliich it is named. 



On the contrary, iron-Avood, AAdiich can be polished like 

 metal, is so dense that savages often employ it to make 

 their Avar-clubs and other formidable Aveapons of 



The finger-nail Avill pierce the fleshy stalk of some eu- 

 phorbias and cause abundance of milky juice to floAv. 

 But, on the other hand, the stalks of some bamboos in 

 India almost tuim the file, and, as Ave have said, are so in- 

 durated with silica, that sparks can be draAvn Avith the steel 

 from them. 



