CHEMICAL ANALYSIS OF SOILS. 201 



lime, and from the analysis of a great variety of soils in New 

 England and the Western States, only a few have any nota- 

 ble portions of this substance, although reposing upon lime- 

 stone rocks. The advantage, therefore, of ascertaining the 

 quantity of this substance, may be derived from simply test- 

 ing the soil with acids ; a method already described. If 

 now the results of this analysis are summed up,' they will be 

 arranged in the following order : 



1. Water of absorption 4.4 



2. Soluble geine 5.1 



3. Phosphate of lime 0.6 



4. Sulphate of lime 1.6 



5. Insoluble geine 7.5 



6. Granitic sand 85.2 



The numbers are supplied from an analysis of 100 grains 

 of a fertile soil in Andover, Mass. 



The method of analysis employed by Dr. C. T. Jackson, 

 differs in some particulars from that of Dr. Dana. The 

 method employed in the analysis of the soils of Rhode Island 

 is here inserted. 



1. Having weighed out a certain quantity, say 100 grains of 

 the fine soil, that has passed the finest sieve, it being weighed 

 upon a square piece of glazed letter-paper, the first step is to 

 dry it thoroughly at a temperature above boiling water, but not 

 sufficient to scorch the paper. The soil being again weighed, 

 its loss of weight is water, and the amount is noted in the la- 

 boratory journal, A. 



2. To ascertain the quantity of organic matter, whether of 

 vegetable or animal origin, we place the dried soil in a platina 

 crucible, cover it closely, and heat it gradually to redness, over 

 an alcohol lamp. By the odor disengaged during the process, 

 we know whether the organic matter is of a vegetable or ani- 

 mal nature, the former having the smell of burning peat, and 

 the latter that of burnt feathers. It is, however, difficult to dis- 

 tinguish the mixed odors, without much practice. Having 

 charred the organic matter, it may now be safely burned out, 

 by placing the open platina crucible with its contents in a clay 

 muffie, open at one end, and exposed to a full red heat. The 

 air circulates in this muffle, and soon burns away all the or- 

 ganic matter, which may be ascertained by repeatedly stirring the 

 soil with a platina rod during its combustion, and noting wheth- 

 er any more particles are burning. After the operation is com- 



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