68G Tbaxsactioxs of the American 'Institute. 



integrated or decomposed, and the soft material lias been carried 

 away to form new beds. Soils originate in three ways. First, by 

 the decay or crumbling of rocks. In some parts of our State if a 

 railroad passes through a hill the matter thrown out, though appar- 

 ently hard rock, soon crumbles and makes an excellent soil. Soils 

 are also made by drift ; that is by the debris of rocks carried from 

 one place to another considerablj'^ remote. This removal is often 

 for remarkable distances. In the north of the State are hills 

 beneath which is trap rock, the crushing of which would make com- 

 paratively a poor soil. But these lands are good because they are 

 made up partly of the dust of limestone rocks that has been carried 

 from the north and deposited upon the trap ridges. The third way 

 in which soils originate is by the solution of rocks and the mechani- 

 cal action of water in river bottoms. Some of our' richest soils are 

 thus composed. The chemical difference in the make-up of soils is 

 very great, and analysis is of great importance, for, if correct, it will 

 correspond to the results developed by actual tillage. For instance, 

 in the north of the State, along the Kittatinny valley, is a soil that 

 upon analysis surprized me by the quantity of rich constituents with 

 which I found it loaded. It is formed from magnesian limestone, 

 which is composed as follows : 



Per cent. Per acre. 



Lime 9^^), or in one foot deep 41,817 lbs. 



Potash 2.90, or in one foot deep 126,324 lbs. 



Phosphoric acid, . . .78, or in one foot deep 39,976 lbs. 



A crop of wheat yielding thirty-five bushels of grain and two tons 

 of straw per acre, takes from the soil, lime, sixteen pounds ; potash, 

 forty pounds ; phosphoric acid, thirty pounds. By comparing the 

 quantity taken in one crop with the amount which remains, one can 

 see how hard it must be to exiiaust such a soil. A thousand years of 

 tillage would not take away all these important elements. The pro- 

 fessor then gave the following as the average composition of seven 

 samples of Cape May soil : 



Pounds 

 Per cent. per acre. 



Lime 0.37 16,117 



Potash 0.42 18,295 



Phosphoric acid 0.11 4,791 



Lime 0.97 42,263 



Potash 0.74 32,234 



Phosphoric acid 0.15 6,534 



