494 THE CHEMISTRY OF CREATION. 



store of fertility against the time when the 

 sea bed upon which these plants will rot and 

 perish may become elevated above the waters, 

 and converted into corn-fields, gardens, and 

 vineyards. 



If, however, sea - weeds merely separated 

 these ingredients for a short time, and when 

 they died if they were again to return to the 

 sea-water, their effect in preserving its con- 

 stant composition would be inconsiderable. 

 Such is not the case. When these plants die, 

 they are cast by the waves upon our shores in 

 vast heaps. On one point of coast where these 

 plants abound, it has been calculated that about 

 30,000 two-horse loads of sea-weed are annually 

 thrown on shore in the months of November 

 and December." This quantity represents not 

 less than the enormous sum of 450,000 Ibs. of 

 sulphuric acid. On the shore they putrefy ; 

 their carbon is dissipated as carbonic acid ; a 

 volatile substance resembling spirit of wine is 

 also given off, according to Professor Forchham- 

 mer; their nitrogen is dispersed as ammonia, 

 and the sulphuric acid, occurring in the form of 

 several sulphates, undergoes decomposition, sul- 

 phurets being formed, and sulphuretted hydro- 

 gen gas being given off. A part of the sulphur 

 also combines with the metallic ingredients of 

 the bed in which the heap of plants live. Thus 



