SOIL COMPOSITION 67 



Investigations by Ingle 1 (as chief chemist for the Transvaal 

 Department of Agriculture) showed that " analyses of Transvaal 

 soils indicate that they are, as compared with English soils, very 

 poor in phosphorus, nitrogen, and lime, but usually rich in po- 

 tassium." 



The Massachusetts Experiment Station (Bulletin 117) reports 

 the following analysis of soil from Turkey, Asia, the amounts per 

 acre being computed for 2 million pounds of surface soil (about 

 6f inches deep). 



Nitrogen 06 per cent, or 1200 pounds per acre. 



Phosphorus " none " 



Potassium 51 percent, or 10,200 pounds per acre. 



Calcium 72 per cent, or 14,400 pounds per acre. 



The 10,200 pounds of acid-soluble potassium is probably much 

 below the total potassium present. 



Professor J. B. Harrison has recently reported 2 that the soil of 

 the Experiment Station Farm in British Guiana, South America, 

 contains 43,600 pounds of total potassium in 2 million of soil. 

 The amount of phosphorus is not reported. 



In the volcanic ash ejected from Vesuvius during the eruption 

 of April 4 and 5, i9o6,Comanducci found .33 per cent of phosphorus 

 and 3.87 per cent of potassium, amounts which correspond to 

 6600 pounds of phosphorus and 77,400 pounds of potassium in 

 2 million pounds of the volcanic material. 



The surface of the United States may be divided into two areas, 

 the glaciated and the unglaciated, as shown on the accompanying 

 map. In general, the great ice sheets moved from north to south, 

 and as they flowed slowly over the face of the earth, they caused 

 enormous erosion of the surface. The eroded material was carried 

 forward in the ice, and much of it was ground to powdered form, 

 while some was reduced only to the form of rounded bowlders, 

 pebbles, and sand grains. This mixture embedded in silt and clay 

 is called glacial drift, or till, or bowlder clay. As the ice melted, 

 the drift material was deposited, sometimes in moraines, or ridges, 

 where for a long period of time the forward movement of the gla- 



1 Journal of Agricultural Science, December, 1908. 



2 West Indian Bulletin (1908), 0, 9. 



