SOILS. 



199 



diiriug" the winter the soil was wholly or in part frozen, as in 1887-'88, 

 1888-'89, and 1890-'91, the greatest drainage was observed after the 

 soil thawed in the spring. 



(4) Soils covered with growing i)lants evaporate considerably more 

 water than bare soils. Evergreen trees (pines) transpire more water 

 than leafy trees (birches), and the latter more than grass. Trees grow- 

 ing on a soil covered with litter under orherwise corresponding circum- 

 stances, give off more water than those growing on uncovered soil. 



Investigations of soil temperatures, 1892-93, J. Sebelien 

 {N'orsic L((n<liii((ii(l.sbhid, Jo {1SI)4), pp. 249-x^')3). — The temperature of 

 the soil at depths of J, ^, and 1 meter was ascertained by tridaily 

 observations for the year JTovember 1, 1892, to October .'Jl, 1893. Two 

 sets of readings were obtained, at Aas Agricultural College and at 

 Jonsberg Agricultural School, both in Korway. The observations are 

 summarized in the paper by groups of 5 days and the results dis- 

 cussed. To allow of more ready comparison of the changes occurring 

 during the year the monthly averages have been calculated in the fol- 

 lowing table, both for the temperature of the soil at the depths given 

 and for the air temperature during the same time. 



Soil iemperutures at different depths hij months. 



Month. 



1892. 



November 

 December. 



1893. 



January . . . 

 February . . 



March 



April 



May 



Juue 



July 



August 



September . 

 October 



Aas Agricultural College. 



Air 

 tempera- 

 ture. 



7. O. 



3.6 

 6.3 



9.1 



10.3 



1.5 



4.1 



9.8 

 10.3 

 17.1 

 U.8 

 8.9 

 4.9 



Soil temperature at depths 

 of— 



1 meter. J meter. 1 meter 



Deg. C. 



3.3 

 0.9 



Beg. G. 



4.2 

 0.8 



Beg. C. 



6.0 

 3.1 



1.8 



1.4 



1.3 



2.1 



7.0 



11.0 



13.6 



14.0 



12.3 



9.2 



Jonsberg Agricultural School. 



Air 

 tempera- 

 ture. 



Beg. G. 



11.7 

 15.4 

 2.4 

 3.8 

 7.9 

 14.2 

 15.9 

 12.9 

 7.4 



Soil temperature at depths 

 of— 



J meter. J meter. 1 meter. 



Beg. C. 



1.3 

 1.5 



3.5 



5.0 



1.9 



1.4 



7.2 



16.0 



17.7 



13.6 



9.0 



5.0 



Beg. G. 



2.8 

 0.7 



1.2 

 2.7 

 1.2 

 0.1 

 2.7 

 12.5 

 15.9 

 13.2 

 9.5 

 6.0 



Beg. O. 



4.5 



2.8 



1.4 



0.4 

 O.l 



9.3 

 11.5 

 11.4 



Note. —Ground covered with snow January 4 to beginning of April at Aas ; from J^Jovember 17 to 

 28 and January 2 to beginning of April at Jonsberg; 1-meter theriuometer at Jiinsberg out of order 

 March 21 to June 6. 



The soil at Aas was heavy clay, while that at Jonsberg was black 

 pulverized alum slate. The results show that the deeper we go into 

 the soil the more evenly the temperature changes and the more slowly 

 the variations are influenced by the great and sudden changes in the 

 temperature of the air. — f. w. woll. 



On the soils of Sao Paulo, Brazil, F. W. Dafert and A. B. U. 

 Cavalcanti {Relat. Inst. Agron. Sao Paulo^ Brazil, 1893, pp. 69-72).— 

 Mechanical and chemical analyses of 33 samjiles of soil from different 



