196 



HOW CKOPS FEED. 



from ever acqiiiriiig the temirjiature it sliortly attains 

 Avhen dry. 



From this c:iusc tlij difil-rcnce in temperature between 

 dry and Avet soil miy often amount to from 10° to 18°. 



On this p!)int, again, Schiibler furnishes us witli the re- 

 sults of his experiments. Columns 4 and 5 in the table 

 below i;ive tlie temperatures whieli the thermometer at- 

 tained when its bulb was immersed in A-arious soils, both 

 wet and dry, eaeh having its natural eolor. (Columns 1 

 and 2 are referred to on i>. 191.) 



Whi t-! Black- Differ- 

 ened.l cned. | ence. 



4 5 



Surface. 



Wet. 



i 121. 3' I 12.G° I 95.2 



13.7= 96.1 



■■rl 14.0" 97.3 



...0': 14.4° 97.7 



^■n.rrl 13.3' 9S.2 



ir,.t) n.r I 9:).i 



1-^1. ri 13.3° I 99.1' 



100.2^! 122.9 

 11(1.3 j 124.3 

 1(17 



99.3° 

 99.3° 



Dry. 



Differ- 

 ence. 



108. 7°| 13.5° 

 109.4°' 13.3° 

 110.5° 13.2° 

 111.7° 14.0° 

 111.4° 13.2' 

 112.6° 13.5° 

 112.1° 13.0° 

 112.1° 12.8° 

 112. 3°i 13.0° 

 113.0° 13.5° 

 113.5°! 14.0° 

 115.3') 13.5° 

 117. 3°| 13.7° 



Magnesia, pure white |133 



Fine carbonate of lime, wiiitc. 



Gvpsiiri), liiiirlit \vhiti---rav 



I'!(.w l:ni(l. ^rav '.. . 



Sandv cl.iv.' vcilowisli 



(Quartz s^aud, bri-ht yellowi.-li-..,:-.;.,-. . . lO'i.!) 



Loam, yclliiwi.'^h .;..". 1(17. s' 



Lime saml, wliitish-trray Kiit.'.i 



Heavvclav soil. vi'll(nvisli-;,M-av 107.1 



Piireclav.blnisb'-urav ' Kii; :; 



Oard.'H mould. blnrki'-li-Lrrav UN.:; 



81nly mai-l, bniwiiisli-ivd. . .' los,;: 



Hiimiis. bnr.viiish-black Ids. .5 



"We note that the difference in fovor of the dry earth is 

 almost nniform.ly 13° to 14°. This difference is the same 

 as obserA'ed between the whitened and blackened speci- 

 mens of the ^ame soils. (Column 3.) 



We observe, liowever, that the wet soil in no case be- 

 comes as warm as tlie same soil Avliitened. AVe notice 

 further that of the wet soils, the dark-colored ones, humus 

 and marl, are most highly he.ated. Further it is seen that 

 coarse lime sand (carbonate of lime) acquires 3° higher 

 temperature than fine carbonate of lime, both Avet, prob- 

 ably because evaporation pi-oceeded more slowly from the 

 coarse than from the fine materials. Again it is plain on 

 com])aring columns 1, 2, and 5, that the gray to yellowish 

 brown and black colors of all the soils, save the first three, 

 assist the elevation of temperature, which rises nearly 



