460 THE CHEMISTRY OF CREATION. 



Sulphuretted hydrogen is, however, one of 

 the products of decomposition on the sea-shore. 

 In the neighbourhood of Copenhagen, the dis- 

 engagement of sulphuretted hydrogen gas is so 

 large that the silver at country places near the 

 shore is deeply blackened by it. But its pro- 

 duction appears to succeed to a sort of ferment- 

 ing process, produced on the shore by the heat, 

 moisture, and presence of organic matters in 

 the mud. Where in tropical countries the 

 forests come down to the beach, which is 

 covered with thickets of mangroves, \vhere the 

 small tides are sufficient alternately to cover 

 and uncover the roots and parts of the trunks 

 of the trees there the mud, the dead leaves, 

 and animal matters putrefy, and give rise to 

 fearful poisons ; and also assist in the develop- 

 ment of sulphuretted hydrogen gas. 



Recent investigations by Professor Forch- 

 hammer teach that important consequences 

 follow upon the putrefaction even of a mass of 

 sea-weed on the shore. When this takes place 

 upon a bed of clay containing iron, a series of 

 chemical decompositions is commenced, which 

 results in the formation of Iron Pyrites, which 

 penetrates the clay. When this is again ex- 

 posed to the weather it oxidizes, and Sulphate 

 of Iron is then formed, which reacts upon the 

 materials around it, and forms Sulphate of 



