UNIVERSITY OF CALIFORNIA PUBLICATIONS 



IN 



AGRICULTURAL SCIENCES 



Vol. 3, No. 7, pp. 131-134 March 15, 1918 



A NEW METHOD OF EXTRACTING THE 

 SOIL SOLUTION 



(A Preliiiiintn'j) Communication) 



BY 



('HAS. B. LIPMAN 



While studying, in 1914, some of the data obtained by Quincke 

 in measuring the forces by which thin water films are held by tiny 

 particles of solid matter, there occurred to the writer a new possibility 

 for a method of extracting the soil solution from soils with optimum 

 moisture contents. By making a simple calculation, I found that if 

 Quincke's figures were correct, particles of .005 mm. in diameter had 

 the power of holding very thin films of water with a force equivalent 

 to about 300,000 lbs. to the square inch. I argued, therefore, that 

 since particles of .005 mm. diameter constitute the "clay" fraction in 

 some mechanical analysis systems and since a large part of soil 

 material may consist of much larger particles, that it should be 

 possible to bring to bear on soils by pressure apparatus already in 

 existence enough force to separate soil particles from some water, 

 even when soils contained relatively small quantities of moisture. It 

 appeared to me, moreover, that the large machines used in engineering- 

 laboratories for testing the strength of materials should be admirably 

 adapted to the task of expressing water from soil if suitable containers 

 for the soil are employed. With this idea as a basis, I started, in the 

 year above mentioned, to experiment first on peat soils with a letter 

 press of the old fashioned sort and found that water could be obtained 

 with it from peat containing 40% of moisture. I then proceeded to 

 have made a special perforated brass plate for the bottom of an iron 

 casing about 12 inches long and about 6 inches in diameter. A quan- 

 tity of clay adobe soil with optimum moisture content was placed in 



