THK CONTENTS OF THK SOIL 29 



25r. The orj^anic matter in soils— tlie plant and animal 

 remains— is removed by burning. Let tlio pupil seouro n cupful 

 of wet soil and carefully weigh it on delioato scales. Then let 

 it dry in the sun, atnl weigh again ; t!ie dilTerence in weight is 



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i ..: 1 > . Aitig the wenriiii; .'i».i> i>i mountain peaks auJ iho formation of 

 Koll nt the bam*. 



du« to the loss or evaporation of water. Now place it in a 

 ino^IiTutely warm oven or on a stove, and after a ffW niinuti s 

 weigh agnin ; more of the water will now have passed off. N«>w 

 thoroughly burn or bake it, nnd weigh ; the losa is now mostly 

 due to the burning of the organic matter, ond part of this 

 matter has passed off as gas. If there is no perceptible loss 

 from the hurning. it is evidi«nco that the sample contained little 

 orgnnic matter. Note the difference in result."* between ciny nnd 

 muck. The pupil may also l>e interested to try to grow plants 

 in the bakeil soil. 



