1 6 Pioneer Labourers 



Quite true that they do not feed by means of their 

 roots — indeed, no seaweeds possess true roots ; and it 

 is quite true, also, that they live upon what they obtain 

 from the water, but surely the taste of it is sufficient to 

 prove that it is not mere water. 



There is no such thing as pure, absolutely pure, 

 water in nature ; and sea-water, which is much heavier 

 than fresh water, contains thirty-five parts of solid 

 matter in every thousand. The rivers are constantly 

 pouring into it small quantities of every sort of mineral 

 substance that can be dissolved, while the sun draws 

 up from it almost pure water, leaving the salts behind 

 to accumulate and help to feed the crops of seaweed, 

 besides providing material for the skeletons of corals 

 and sponges and the shells and bones of other sea- 

 creatures. 



All plants, then — whether they tower aloft like the 

 giants of the tropical forest, or send out streamers two 

 or three hundred feet in length like the Giant Kelp of 

 the Atlantic Ocean ; whether they are so minute as to 

 be altogether invisible to the naked eye, and whether 

 they live in earth or in water — are alike in this, that 

 they live upon other food besides mere air and 

 water. 



We may easily satisfy ourselves of this by burning a 

 bit of wood, a few grains of corn, or any other vege- 

 table matter. When it has burnt as long as there is 

 anything to burn, and all the gases and water it con- 

 tained are driven away, a small quantity of ash will 

 remain, consisting of salts, or compounds of various 

 metals. The whole amount is usually very small — so 

 small that we might perhaps be disposed to think it 

 could not be of any very great consequence. 



