EXERCISE 69 A 



WHAT IS THE CHARACTER OF THAT PART OF THE SOIL IN WHICH NO PARTICLES 



CAN BE SEEN WITH THE UNAIDED EYE? 



Materials. A microscope ; some of the muddy water and finest of the soil particles from the 

 preceding experiment. 



Directions. Place a drop of the muddy water from the preceding experiment on a glass slide, and 

 examine with the low power of the microscope. (Do not use the high power of the microscope unless 

 so directed by the teacher.) Examine also a very little of the top part of the sediment mixed with 

 water on the slide. There should be only enough sediment to make the water on the slide appear 

 cloudy. Examine a third sample from that part of the sediment in which very small particles are 

 visible to the naked eye. 



Describe the material in each case, and state what is shown regarding the structure of soil. 



Additional problems. Are there small soil particles which seem to differ from the large ones only in size ? 

 Are there small particles which differ from large ones in their nature as well as in size ? 

 Does a fertile soil usually contain more or fewer of the fine soil particles than do poor soils ? 



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