SPECIFIC HEAT OF SOILS 



165 



one unit of heat were imparted to an equal weight of water. 

 The calculation may of course be varied so as to show the 

 specific heat of equal volumes. The following determinations 

 of the specific heat of various constituents of soil are quoted 

 from C. Lang. 



TABLE XXVHI 



SPECIFIC HEAT OF SOIL CONSTITUENTS 



Looking first at the calculations by weight, it appears that 

 the same quantity of heat which would be required to raise 

 i Ib. of water i F., would suffice to raise about 5 Ib. of dry 

 chalk or quartz sand, and 2 Ib. of peat, to the same temper- 

 ature. Or, looking only at the solid soil constituents, the same 

 amount of heat from the sun would equally warm about 

 8 Ib. of quartz sand and 3 Ib. of perfectly dry peat. It 

 follows, as a matter of course, that when cooling, 3 Ib. of peat 

 will evolve as much heat as 8 Ib. of quartz sand ; and 5 Ib. of 

 chalk or quartz as much heat as I Ib. of water. 



The specific heat of a perfectly dry arable soil, reckoned by 

 weight, will generally be -20- -23. It follows that 4-5 Ib. of 

 dry soil, and i Ib. of water, will be raised to the same tem- 

 perature by the same supply of heat. 



