CONTENTS 



Page 



Introduction 1 



I Methods of investigating light vision (as contrasted with color vision). . 4 



1. Sources of stimulus 4 



a. Sun 



b. Nernst lamp 



c. Tungsten lamp 



d. Carbon incandescents 



e. Carbon arcs 



f. Acetylene lamp 



g. Gas lamps 



h. Oil lamps and candles 

 i. Recommendations concerning sources for tests of light vision 



2. Measurements of stinmlus 11 



a. Photometry of white light stimuli 



b. Radiometry of white light stimuli 



3. Application of stimulus to animal 14 



a. C'ommon methods 



b. Method recommended 



II. Methods of investigating visual size, form, and distance perception 15 



1. Size perception 15 



2. Form perception 16 



3. Distance perception 16 



III. Description of standardized apparatus and method recommended for the 



study of light, size, form, and distance perception 17 



1. Light or " brightness " apparatus 17 



2. Points of method 26 



IV. Methods of investigating color vision 28 



1. Sources of stimulus 28 



a. Sun 



b. Nernst lamp 



c. Tungsten lamp 



d. Acetylene 



e. Carbon arcs 



f. Recommendations concerning sources for tests of color vision 



2. Methods of obtaining and applying stimulus 30 



a. Reflection method 



Colored papers 

 Colored cloths 

 Oil pigments on opaque surfaces 



b. Transmission method 



Glasses 



Gelatines 



Solutions 



c. Dispersion method 



Grating spectra 

 Prismatic spectra 



3. Measurements of stimulus 45 



iii 



