LIST OF ILLUSTRATIONS. 



FIC9. TACK. 



1. Diflferencos of mean annual temperatures of soil (W—0) 42 



2. DiBereuce of temperature (W— O) at the depth of 4 feet 44 



3. Difterence of soil temperature (W— O), all stations — German observatories . 45 



4. Dift'erences of soil temperature (woods and open fields). Comparison of 



deciduous and evergreen trees (W— 0) 47 



5. Differences of soil temperature (woods and open fields). Comparison of 



elevations above sea level (W — O) 48 



6. Differences of temperature for young trees, Lintzel Station, woods and 



open fields (W-0) - 49 



7. Effects of litter on soil temperature (littered surface— bare). Wollny's 



observations ^9 



8. Difference of soil temjjerature, under sod and bare surface (sod — bare). 



Becquerel's observations 50 



9. Forest air temperature differeuces, W— O. Geruian stations 52 



10, II, 12, 13, 14, 15, 16, and 17. Forest air temperature differences, woods and 



open fields (W — O), at Friedrichsrode, Hagenau, Sonnenberg, Ebers- 



walde, Schoo, Marienthal, Hadersleben, and average 55, 57 



18, 19, 20, 21, and 22. Forest air temperature, difference of woods and open 

 fields (W — O), deciduous trees, evergreen trees, elevated stations, near 

 sea level, and young forest (Lintzel) 59 



23. Forest air temi>eratiire differences for the year at height of the tree top 



(W— O) - <>2 



24, 25,20, 27, 28, 29, 30, 31, and 32. Tree- top temperature, differences (W— O) 



at Friedrichsrode, Kberswalde, St. Johann, Carlsberg, Sonnenberg, 

 Kurwien, Ilagenau, Schoo, Neumath 64, 65 



33. Average differences of tree-top temperature, sixteen German stations 



(W— O) 66 



34. Tree-top temperature differences for four stations, with average height 



of 24 feet 6<5 



35. Tree-top temperature differeuces for four stations with average height of 



46 feet *^7 



36. Tree-top temperature diftorences, German stations (W— 0), deciduous 



trees ^^ 



37. Tree-top temperature differences, German stations, evergreen trees 67 



38. Vertical temperature, gradient in woods, degrees Fahrenheit for a hun- 



dred feet Gti 



39. Forest temperature differences at Ilalatte vinder deciduous forest 6J' 



40. Forest temperature differences at Ermenonville under pines, soil, coarse 



bare sand '^ 



41. Forest temperature differences above trees, from Fautrat'e observations. 70 



42. Vertical temperature gradients from observations above trees 7C 



43. Tree temperature, Geneva observations '^^ 



44. Temperature differeucea between tree and air '^ 



7 



