206 EARL W. BENJAMIN 



arranged in a tray. These standard eggs were then carefully matched 

 with their respective colors in Repertoire de Couleurs* (Plate VII). 



The color of eggshells is not permanent and will fade considerably 

 if exposed to the light for any great length of time. The practice was 

 tried of coating the shells with various preparations intended to preserve 

 their color, but this was not successful, as all these preparations contained 

 so much color in themselves that the color of the shells thus coated was 

 materially changed. The method finally followed was to use, as standards, 

 eggs with the natural surface. The tray of eggs was kept covered with 

 a black cloth except when in use, and the standard eggs were replaced 

 with others of identical color at intervals varying with the length of time 

 they were used. 



A clear north light is necessary for accurate color selection, and one 

 must have a trained eye in order to be sure of recording the correct color. 

 The terms chalk-white, cream-tinted, and brown-tinted are used merely 

 to designate the three groups of colors, in order to show the type of eggs 

 selected for each lot. The color recording was done by one person early 

 in the experiment and by another person later. A trial was made of 

 color recording by several inexperienced persons on the same set of eggs 

 for several succeeding days, and the percentage of error was found to be 

 very slight. The same standard scale of colors was used thruout the 

 work. The colors were numbered as shown in Plate VII, and these num- 

 bers were used in the correlations and other calculations. 



METHODS COMMON TO STUDIES OF ALL THE CHARACTERS 



The chicks used in this study were reared by standard methods, in 

 colony houses with the other experimental chicks on the Cornell experi- 

 mental farm. Previous to 1913 the mature birds were kept in a narrow 

 house divided into nine pens, one pen for each of the nine characters. 

 Under these conditions the one selected male bird for each pen was allowed 

 freedom in the pen. During the 1913 breeding season and after, individual 

 mating coops were installed, and individual mating was followed for the 

 remainder of the experiment. New houses were used for the stock after 

 1913 (fig. 11). All feeding, trap-nesting, and other details of management 



8 Repertoire de couleurs. Published by La Socie'te Frangaise des Chrysanthe'mistes and Ren6 Oberthur, 

 with the collaboration of Henri Dauthenay and others. 1905. 



