294 soils: properties and management 



1. Specific heat 



2. Absorption 



3. Radiation 



4. Conductivity and convection 



5. Evaporation of moisture 



6. Organic decay 



7. Slope 



8. Heat supply and its effects 



211. Specific heat. — The specific heat of any material 

 may be defined as its thermal capacity as compared with 

 that of water. It is the ratio of the quantity of heat 

 required to raise the temperature of a given weight of 

 the substance one degree Centigrade to the quantity 

 needed to change an equal weight of water from 19.5° 

 to 20.5° Centigrade. A knowledge of the specific heat 

 of soil is important because of the general light it sheds 

 on the warming-up of a soil in spring and on its rate of 

 cooling in autumn. The data from a number of investi- 

 gations, in the order of their priority, is here quoted, 

 the calculations being based on dry soil : — 



Weight Specific Heat of Soils 



Pfaundler 1 (1866) 



Liebenberg 2 (1878) 



1 Pfaundler, L. Ueber die Warme Oapacitat Verschiedener 

 Bodenarten und deren Einfluss auf die Pflanze. Ann. d. 

 Physik u. Chemie, Band 205, Seite 102-135. Leipzig, 1866. 



2 Liebenberg, R. von. See Lang, C. Ueber Warme Capa- 

 citat der Bodenconstituenten. Forsch. a. d. Gebiete d. Agri.- 

 Physik, Band I, Siete 118. 1878. 



