Apr. -Sept., 1915 



Illustrations xv 



Page 



Fig. 13. Curve showing the mortality among 25 control gipsy-moth caterpillars. 124 



14. Curve showing the mortality among 40 gipsy-moth caterpillars fed with 



wilt virus after filtration through Berkefeld filter 124 



15. Curve showing the mortality among 40 gipsy- moth caterpillars fed with 



unfiltered wilt virus 125 



16. Curve showing the mortality among 20 control gipsy-moth caterpillars. 125 



17. Ciu've showing the mortality among 50 gipsy- moth caterpillars imder 



conditions approximating those in the field 125 



Effect op Temperature on Germination and Growth of the 

 Common Potato-Scab Organism 



Fig. I. Chart showing the relation of temperature to time of germination 130 



Notes on the Hydrocyanic-Acid Content op Sorghum 



Fig. I. Curve showing the effect of available nitrogen on the hydrocyanic-acid 



content of sorghum 180 



2. Curve showing the distribution of hydrocyanic acid in sorghum 183 



Effect on Son. Moisture of Changes in the Surface Tension op the 

 Soil Solution Brought About by the Addition op Soluble Salts 



Fig. I. Curve showing the differences in the moisture content of treated and 



check sandy-loam soils i8g 



2. Curve showing the differences in the moisture content of treated and 



check clay-loam soils 190 



Methods of Bacterial Analyses of Air 



Fig. I . Standard aeroscope 347 



2. Modified standard aeroscope 347 



3. Rettger's aeroscope 348 



Tensile Strength and Elasticity op Wool 



Fig. I. Curve showing the regularity of stretch and the abrupt break of merino 



wool after the elastic limit is passed 382 



2. Ciu-ve showing Yotmg's modulus of elasticity of merino wool at differ- 



ent stresses 383 



3. Diagram for plotting curves by means of which the percentage of ac- 



curacy of the tensile strength of wool when comparing two sets of 

 observations may be exactly calculated 386 



4. Curve of ordinary probability. The abscissae are taken as a variation 



in strength of a given fiber from the mean strength of all the fibers 

 and the ordinates are proportional to the probability that such a fiber 

 exists 387 



Influence op Hybridization and Cross-Pollination on the Water 

 Requirement op Plants 



Fig. I. Graph showing relation between the parental divergence ( t ) ^^d the 



hybrid divergence from the parental mean (_?£_) where a = water 



\a+t>/' 

 requirement of less efficient parent; 6=water requirement of more 

 efficient parent; c=water requirement of hybrid 397 



