1918] Liptnan: A New Method of Extracting the Soil Solution 133 



can be used successfully for purposes of obtaining the soil solution 

 as it exists in relatively thin films around the soil particles. The pro- 

 cedure is rapid, clean, and of high efficiency. With further improve- 

 ments in apparatus which we are now planning, the method should 

 supplant all other methods known today, including even the Morgan 

 procedure. 1 None of the other methods are really satisfactory and 

 even that of Morgan is laborious and slow, and introduces the factor 

 of oil, which complicates and renders it extremely time-consuming 

 and untidy. Within recent months, 1 have noted in the literature 

 that attempts have been made by Bamann, Marz, and Bauer 2 and by 

 Van Zyl 3 to use direct pressure as I have done. The original papers 

 detailing the work of these investigations are not available to me, 

 however, and I am almost entirely in the dark as to the details of 

 the method and, in one case, of the magnitude of the pressures cm- 

 ployed. The maximum pressure thus far exerted in my method has 

 been approximately 53,000 lbs. to the square inch, whereas Bamann 

 and his associates with a hydraulic press seem to have used only about 

 1500 lbs. per square inch. Moreover, if the abstract of their paper 

 which is available to me has interpreted the authors correctly, their 

 method is only applicable to soils made up of very fine particles or 

 containing much organic matter. My experience has always been 

 that the coarsest soils are always the easiest to manage in expressing 

 water from them. Indeed, until recently, the fine grained soils, as 

 above intimated, gave me considerable trouble, because they would 

 creep out of the container in fine ribbons, while the pressure was 

 being applied. Mr. Wiskocil's suggestion of a thin casing of sand for 

 the fine grained loam or clay loam has obviated that difficulty, how- 

 ever. I judge from my experience, moreover, that Bamann and his 

 coworkers must have used very wet soil or they could not possibly 

 have secured solutions from them at the low pressure mentioned. The 

 abstract of Van Zyl's paper says nothing about the pressure used by 

 him and the manner in which it was applied. The statement is that 

 the soil can be "squeezed." Other comparisons of my method with 

 the comparable ones just discussed will be given in a later paper. 



Finally, it may not be superfluous to emphasize the importance to 

 all soil studies of the proper use of the method which I have described 

 above. It allows of the direct determination of the concentration of 



i Soil Science, vol. 3, p. 531 (1917). 



2 Int. Mitteil. Bodenkunde, vol. 6, p. 27 (1916), cited from Chem. Abst., vol. 11, 

 no. 22, p. 3078 (1917). 



3 Jour. Landw., vol. 64, p. 201 (1916), cited from E. S. R., vol. 36, p. 720. 



