TEMPERATUEE OF SOIL. 129 



The temperature at 2 p. m. is often excessive, and those combinations of 

 soil would seem to be best adapted to vegetable grov/th which maintain an 

 elevated temperature at other portions of the day, e. g., at 7 a. m., and 9 p. 

 M. Tried by this standard, we find that clay, mixed with 13 j^er cent, 

 humus, has a temperature higher by 2°. 08 than tile clay; and sand, with 12 

 per cent, humus, has a temperature higher by 2". 68 than pure sand, and 

 this relative excess of temperature is maintained through the whole season 

 of active vegetable growth, viz., from 1st of May till 1st of October. 



It will appear from this, that the farmer has an indirect control over the 

 climate of his fields, through this relation of humus to temperature of soils, 

 when mixed with them. The popular opinion in regard to muck is expressed 

 in the epithet "frosty," so generally applied to it. One reason for regard- 

 ing a mucky soil as j)redisposed to frost, probably arises from the position it 

 usually occupies, viz., at the bottom of valleys, and other low i^ositions. 

 Into these valleys the air, rendered denser from a loss of temperature, will 

 pour from all the surrounding high lands, and hence a lake of cold air will 

 fill each valley, and a slight reduction of temperature by radiation will 

 result in frost, and this frost is the result of position, and does not neces- 

 sarily arise from the nature of the soil in such valley. Persons who travel 

 in an open carriage at night in summer, and when the air is still, are aware 

 how abrupt is the passage from comparatively warm air on the highlands to 

 the cold air filling a valley, and the equally abrupt change as they rise out 

 of the valley into the warm air covering the opposite bank. 



All of which is respectfully submitted. 



R. C. KEDZIE. 



Lapsing, December, 1868. 



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