CHAPTER VI. MOISTURE OF THE SOIL 
CHAPTER VII. MISCELLANEOUS RELATIONS 
CHAPTER VIII. RELATION OF PLANTS TO ATMOSPHERIC NITROGEN 
12 
CHAPTER V. THE METHODS OF MEASURING DIRECT OR DIFFUSE SUNSHINE 
AS TO INTENSITY OR DURATION 
Theoretical relation of direct and diffused sunshine (Clausius) ___----- 
Total insolation, direct and diffused (Marié-Davy) .-_ -.-_---_-_------ 
Theoretical formule for actinometer (Arago-Davy; Marié-Davy; Fer- 
TOL) 2 on ke baat oe Re A ree eS ee ee oe ee 
Intensity and duration of sunshine at Montsouris ( Marié- =DAVy)) sea nae 
Relative total heat received from sun and sky during any day by hori- 
ZONA SUPLAGCES a CAsy ALY OTIC ty) ee 
Relative total heat received during certain months (Aymonnet) 
Photo-chemical intensity of sunshine (Bunsen; Roscoe) 
Photographic intensity of sunshine (Vogel; Weber) 
Marchand’s self-registering chemical actinometer___._____-____ ______- 
Comparison of Marchand’s and Marié-Davy’s results (Radan) 
Violle’s: conjugate: bulls... oes oe a ee ee 
Bellani’s radiometer or vaporization actinometer (Descroix) 
Arago’s cyanometer and Desain’s thermo-electric actinometer 
Duration of sunshine— 
Recorded at United States Signal Service stations 
Recorded at Wannipes:, Manitoparse sees 22 ee ee eee 
Total possible duration of sunshine, by decades (Schott; Libbey) 
Invpenerall 4 . 22 5-42 Lape eee gee oe ee Se eae 
Evaporation from the surface of fresh water in evaporometer (Descroix; 
Mitzeerald-sPichessEvuSselllli) gas saree re ae aes eae 
Cultivation diminishes surface-soil evaporation (Grarterant) 
Percolation (Welitschkowsky; Whitney; Goff) ..______._....__--_--__- 
Available moisture (Wollny; Haberlandt; Seignette) _____.________--- 
Transpiration (Hoehner; Wollny; Risler; Marié-Davy; Perret) 
Relation of plants to moisture of soil (Wollny) ._.-. ---- ...-------- 
Relation of water to crops (Ilionkoff; Haberlandt; Hellriegel; Fitt- 
bogen; Birner; Heinrich; Wollny; Sorauer) 
Rainfall and sugar beets (Briem; Grassmann) 
Rapid thawsoc.2- 2 ses ae eee ee 1 Soe ge SS eee 
Wind -2.cee ni 5.5 2.25 eis oe ae Bak ee eee ee 
The organic dust of the atmosphere (Serafina; Arata) 
Atmospheric electricity (Wisliczenus; Marié-Davy) 
Imi@enerall 224! 259 3 he Sse ea ie ne ee ee ee 
The amount of nitrogen brought down by the rain to the soil (Marieé- 
Dayy:; Muntz; Marcano).. (22222-2522 oe ee See ee 
Nitrogen directly absorbed by soil (Schloesing) --__.---_.-____------_- 
Fixation of nitrogen by plants (Hellriegel and Wilfarth; Bréal; Lawes 
and Gilbert; Frank; Berthelot; Heraeus; Warington; Maquenne; 
Wheeler; Leone; Woods; Petermann; Pagnoul; Salkowsky) 
CHAPTER IX. RELATIONS OF CROPS TO MANURES AND FERTILIZERS, AND 
ROTATION 
Artificial fertilizers and manures (Sanborn; Ohio; Ladd; Prize crops 
of 1889) 
Page. 
