64 



J^xpcv'nnrnt A 



(). ■'). 



KATK OF I'KKCOLATIOX OK WATEK 'I'lIKorOH .SOILS. 



The series of tu])es ( (it;. 14) having l)een lille<l within 1 inch of the overflow pipes 

 with soils Nos. 1, 2, 3, 4, and 5, the compacting niacliinc is used. 



After each measure of soil was put in the weight is dropped twice from the 6-inch 

 mark. The surface of the soil in each tuhe is covered with 1 inch of coarse gravel 

 to prevent the soil being distur))ed by Howing water. 



See that all tubes are connected In- rubl)er tu))ing and the extreme ends of small 

 tul)es corked. 



Pour in distilled w ater gently and keej) the cylinders almost level full. After the 

 flow into the glass flasks has become uniform, note the number of cubic centimeters 

 which flow through in half an hour. Determine this by measuring in a graduated 

 cvHnder. 





Fig. 1-4. — Hate of pcrcolati iii nf water through soils. 



The cliaracter of soils used may be examined in the boxes in the laboratory. The 

 tubes are numbered to correspon<l witli the soil muid)ers. 



This experiment l)rings out the differences between soils in regard to the I'ate of 

 percolation of water through them. Other things equal, it is desirable that a soil 

 should allow water to pass through slowly, liolding moisture the greatest length of 

 time within the reach of crop roots. 



Expt'rhiifiit No. 6. 



KATK OF FLOW OF .VIR THKOUGII SOILS. 



Soils Nos. 1, 2, o, 4, and 5 are used in this experiment. The cylinder numbers 

 correspond with the soil lunnbers. 



The compacting machine was used in filling the cylinders (fig. 15). After each 

 measure of soil, the weight was dropped three times from the 12-inch mark. 



Open the cock on the copper cylinder and detach the hook holding the weights. 

 Allow the copper cylinder to sink by its own weight. Attach the rubber tube to 

 soil tube No. 1. Attach the weight hook and note the number of degrees passed by 

 the pointer in 10 minutes or a longer time, if it be necessary in case of the fine- 

 grained soils. Record the weight for each of the five soils, calculating the weight per 

 hour. 



