BULLETIN 
OF THE 
NUTTALL ORNITHOLOGICAL CLUB. 
vol. vii. July* 1882. No. 3. 
THE COLORS OF FEATHERS. 
BY J. AMORY JEFFRIES. 
Feathers have been studied from the earliest days of the micro- 
scope, indeed long before the modern microscope came into 
existence. Malpighei, Hooke and Leeuwenhoek all wrote on the 
subject, and not a little of our knowledge dates from their time. 
Since then authors have constantly written on feathers and their 
colors, until the papers on the subject may be counted by hun- 
dreds. Accordingly little that is new can be expected from this 
short article, nor even a history of the literature of the subject. 
•My only object is to give an idea, so far as is known, how the 
colors of feathers are produced, the literature of the subject being 
out of the track of most American ornithologists. 
Color may be the result of any one or more of the following 
causes : a pigment, interference and diffraction of light in their 
various phases, fluorescence, and phosphorescence. Of these 
causes only three have been called upon to explain the colors of 
feathers, the last two apparently playing no part. The fluores- 
cence noted by Dr. Krukenberg in solutions of certain feather- 
pigments probably plays no part, or at most an insignificant one, 
in the colors of feathers. Pigments act by absorbing all rays of 
light but those which enter into their color, that is turn them into 
heat. 
