CONTENTS. 



Page. 



Letter of Tr.u^smittal 3 



Preface - 5 



Table of Contents - - 11 



Part I.— Laboratory Work, Physiological and Experimental. 



Chapter I. General Remarks 15 



The vital principle— Cellular and chemical structiire 15 



General relations of the seed and plant to the air and the soil * 18 



Importance of climatic laboratories (De CandoUe) 23 



Chapter II. Germination 28 



Influence of uniform temperature on germination of seed ( De CandoUe) . 28 



Influence of temperature and moisture on germination (Sturtevant) 37 



Influence of light and heat on germination (Pauchon) 37 



Chapter III. The Temperature of the Soil 53 



Observations at Houghton Farm and Geneva. N. Y., by Penhallow . .- 53 



Observations by Goff 53 



Observations of temperature of manured soils in Japan by Georgeson _ 54 



Influence of rain on temperature of the soil at Munich (K. Singer) 54 



Soil temperatures as affected by surface slope and covering (Wollny) _ . 57 



Soil temperatures observed at Greenwich, England 58 



Soil temperatures observed at Brookings, S. Dak 59 



Soil temperatures observed at Auburn, Ala 61 



Soil temperatures observed at Pendleton, Oreg 62 



Soil temperatures observed at Montreal. Canada 63 



Methods of measuring soil temperatures (Whitney; Emory; Menden- 



hall) 65 



Chapter IV. The Infllt:nce of Sunshine on Assimilation and Trans- 

 piration 67 



Chemistry of assimilation (Abbott) 67 



Sunshine and transpiration (Marie- Davy: Deherain) ' 69 



Annual distribution of svmshine ( Humboldt) 72 



^otal quantity of heat required to ripen grain ( Boussingault) 73 



The sunshine and heat required to ripen grain (Tisseraud ) 73 



>,,^^The sunshine and heat required to form chlorophyl (Marie-Davy) 75 



Influent'e of absorbent media on chlorophyl (Engelmann) 77 



Influence of the .supply of sap (Laurent) 77 



Climate and the location of chlorophyl cells (Guntz) 77 



The influence of cloud and fog ( Marie-Davy) 78 



Influence of shade on development (Hellriegel) . 79 



Influence of long and short waves of light ( Vochting; Sachs) 79 



Influence of dryness and sunlight on development of tubers (Knight; 



Langeuthal; Wollny) 80 



(11) 



