60 



soils selected on the Ohio Stiite University farm with rcferoucc to their 

 dift'erences in textiii'(> and crop producing powci" 



No. 1. Muck soil. Selected from a very fertile cornfield. 



No. 2. First bottom alluvial loam. Very fertile. 



No. P). Second bottom sandy loam with considerable clay. 



No. 4. Fine sand (0.25 millimeter to 0.1 millimeter in diameter). 



No. ."). Coarse sand (0..5 millimetei- to o.'2r> millimeter in diameter). 



The soils are l>rouirht fi'om the lields and air-dried in the laboratorv. 

 Nund)crs 1 to 8 are sifted through a ^^-millimeter sieve having- circular 

 holes, and numbers 4 and o through liner sieves. The soils are then 

 placed in ninnltered 1)ins in the laboratory. 



The following is a list of the laboratorv expei-iments with descrip- 

 tions and illusti'ations of each: 



Kxpf nine lit \ii. I. 



DETEUMINATION OF SPECil'MC (lUAVlTV OF f>OU>S. 



This expt'riinent. shows weiglits of the various soils as compared with the weights 

 of equal vohunes of water. The speuitic gravity of most soilq^is about 2.5 — that is, 

 soil calculated free of air space weighs 2.5 times as much as an cijual volume of 



Fiii. lu.— Appanitus for determining specific gravity of soils. 



water. The more organic matter a soil contains the less its specific gravity. In 

 general, the specific; gravity of a soil decreases inversely as its content of organic 

 matter. Specific gravity must not he confused with apparent specific gravity, which 

 will be explained in experiment No. 2. 



With a fiask of 50 c-ubic centimeters capacity and jirovided with a ground-glass 

 stopper, drawn out to an open capillary tube (fig. 10), <letermine specific gravity of 

 four soils which will be jn-ovided — Nos. 1, 2, 3, and 4. 



Fill flask with distilled water so that no air huhbles appear after the grouml-glass 

 stopper is inserted. Note temperature of water in flask. Wipe flask ilry and weigh. 



