ii PREFACE 



colors, but the effort was successful only to the extent that it was 

 an improvement on its predecessors; and, although still the 

 standard of color nomenclature among zoologists and many other 

 naturalists, it nevertheless is seriously defective in the altogether 

 inadequate number of colors represented, and in their unscientific 

 arrangement. Fully realizing his failure, the author, some two or 

 three years later, began to devise plans, gather materials, and 

 acquire special knowledge of the subject, in the hope that he might 

 some day be able to prepare a new work which would fully meet 

 the needs of all who have use for it. Unfortunately, his time has 

 been so fully occupied with other matters that progress has neces- 

 sarily been slow ; but after more than twenty years of sporadic 

 effort it has at last been completed. 



Acknowledgments are due to so many friends for helpful 

 suggestions that it is hardly possible to name them all, or to specify 

 the extent or kind of help which each has rendered; but special men- 

 tion should be made of Mr. Lewis E. jEWEUy, of Johns Hopkins 

 University; Dr. R. M. Strong, of the University of Chicago; 

 Prof. W. J. Spix^man, of the U. S. Department of Agriculture; 

 Mr. Wigwams WeiXH, of the U. S. Signal Service ; Mr. Mii/ton 

 Bradley, of Springfield, Mass.; Dr. P. G. Nutting, of the U. S. 

 Bureau of Standards ; Mr. P. L. Ricker, of the Bureau of Plant 

 Industry, U. S. Department of Agriculture; and Mr. J. L. 

 Ridgway, of the U. S. Geological Survey. The late Professor 

 S. P. IvANGley, then Secretary of the Smithsonian Institution, was 

 good enough to take a kindly interest in this undertaking and gave 

 the author assistance for which he is glad to make acknowledg- 

 ment. More than to all others, however, is the author deeply 

 indebted to Mr. John K. Thayer, of Lancaster, Mass., and Senor 

 Don Jose C. Zeledon, of San Jose, Costa Rica, for aid so indis- 

 pensible that without it the work could not have been completed. 



To Dr. G. Grubber & Co., of Leipzig, Germany, the author 

 is under obligations for the gift of a nearly complete set of their 

 celebrated coal-tar dyes, which have proven quite necessary to the 

 work, especially in the coloring of the Maxwell disks on which the 

 color scheme is based. 



The reproduction of the plates has been a difficult matter, 

 involving not only expensive experimentation, but more than three 



