TEXTURE AND STRUCTURE OF SOILS 



49 



Determine in the same way the apparent specific gravity of the 

 clay when loose and when compact. 



Compare the figures from each soil and explain the reasons for 

 the differences observed. 



Calculate the weight per cubic foot and acre foot of the sand and 

 clay when loose and when compact. 



Fig. 8. — Equipment for the determination of the apparent specific 

 gravity of soil, consisting of a balance, a set of weights and a 100 c.c. gradu- 

 ated cylinder. 



Exercise VIII. — Calculation of pore space. 



Materials. — Data from Exercise VII. 



Procedure. — Using 2.7 as the absolute specific gravity of soils 

 and the data from the preceding exercise, calculate the pore space 

 on loose and compact clay and sand respectively by means of the 

 following formula. 



% pore space = 100 - [" ap-sp-gr. x l^Ql  

 Labs. sp. gr. 1 J 



Be ready to explain the reasons and significance of the results 

 obtained. 



1 Ap. sp. gr. means apparent specific gravity. Abs. sp. gr. means absolute 

 specific gravity. 

 E 



