THE FOOD OF PLANTS. 283 



ful examination to afford potash, and hence we may 

 look with confidence to the rapid cheapening of 

 this most useful product. 



Ten years ago who could have supposed that 

 along the river beds upon the coast of South Car- 

 olina there were millions of tons of rocks holding 

 that important element of plant food, phosphoric 

 acid ? These rocks were indeed known, but their 

 important character was not understood. The 

 phosphatic rock beds of that region extend over an 

 area of several hundred square miles, and in some 

 places they are twelve feet thick. It is estimated 

 that from five hundred to a thousand tons underlie 

 each acre. How vast is this supply of an agent of 

 the highest importance to agriculture, and what a 

 source of national wealth it opens to us ! 



Two important considerations force themselves 

 upon our attention. One is, that nature has pro- 

 vided ample materials to supply all our wants. In 

 mountains, and caverns, and streams, she has depos- 

 ited all elements and combinations which are essen- 

 tial for our well-being and progi-ess, and it is un- 

 reasonable and wicked to doubt regarding the 

 -future. The other is, that science must be sustained 

 and fostered, for it holds the key which is alone 

 capable of unlocking nature's storehouses, and 

 bringing forth from the dark recesses of earth those 

 rich materials which have been provided for our 

 sustentation and happiness. 



