1922] EATON—SULPHUR CONTENT OF SOILS 37 
lack in the data is information as to the previous history of the 
soils from which the samples were taken. In a number of instances 
I have data as to the productivity of the soils, and information as 
to the amount of manure and fertilizer that had been applied to 
the soils in recent years, but in some cases it was impossible to 
secure this information. Also, the data would have more general 
significance, perhaps, if in all cases the names of the soil types could 
Per Cent 
L | i i 
Alabama Maryland Oklahoma Central States Chicago 
Fic. 1.—Curve comparing sulphur, phosphorus, and organic matter content of 
five groups of soils ; organic matter divided by 200. 
be given, but this was only possible for the Maryland soils. In 
most instances, however, the samples were taken from important 
agricultural soils, and therefore the data should have significance 
i adding to the information as to the sulphur content of the 
agricultural soils of different sections of the United States. All 
the results are figured on the basis of the oven-dry weight. The 
data concerning the pounds of sulphur per acre were obtained from 
the percentage of sulphur determined by analysis, by assuming 
that an acre of soil 6. 5-7 inches in depth weighs 2,000,000 pounds. 
