38 



Mycologia 



THese will be named as far as possible, it being manifestly im- 

 possible to satisfactorily name all of them, and in addition each 

 horizontal row will be numbered and the vertical rows lettered, 

 intermediate figures and letters between each row being used to 

 represent intermediate shades or tints when that degree of accu- 

 racy is necessary. Instead of the degree of variation between 

 blocks of color in various parts of the work being very unequal, 

 as in all previous color guides of any size, the intermediate shades, 

 tints and hues are determined by a uniform scale of percentages 

 by the use of Maxwell's color wheel. There will be a probable 

 edition of 2,500 copies, the volumes being about five and a half 

 by eight inches, and one inch thick. For field use it is expected 

 about 800 of these copies will have their margin trimmed and 

 be bound in a flexible leather binding, easily fitting a man's coat 

 pocket. The price with board covers will be about $5.00. The 

 only work extant which approaches this in any respect is the 

 Repertoire de Couleurs of the Societe Francaise des Chrysanthe- 

 mistes, containing 1,385 color shades and tints, of which only 

 about 365 are named, and no method is provided for designating 

 the others. It consists of two bulky volumes of loose plates in 

 portfolios, many of the intermediate shades, tints and hues are 

 too nearly alike, and a prohibitive import duty brings the price in 

 this country to about $10.00. The paper is also too heavy, and its 

 form is entirely unsuited for field work. 



Bureau of Plant Industry, 

 Washington, D. C. 



