Vol iy | Correspondence. 509 
of a solid body altogether; the two colors seem to blend into the most 
inconspicuous grey, and at close quarters the effect is as of bars of light 
seen through the branches of shrubs. I have found myself in the forest 
gazing at what I supposed to be a solitary zebra, its presence betrayed by 
some motion due to my approach, and suddenly realized that I was sur- 
rounded by an entire herd which were all invisible until they moved. 
“The motionlessness of wild game in the field when danger is near is 
well known.”” (Henry Drummond, D. D., in ‘Tropical Africa,’ 1888.) 
This antedates all my writing on concealing coloration, and is the only 
publication that I know that does so. 
Those European armies’ universal adoption of concealment-by-pattern 
of snipers, autos, tanks, tents, etc., adds interest to the study of this uni- 
versal animal-world principle, which the English and the Swiss naturalists 
assure me these armies have all got from my book. 
It is somewhat amusing that while Europe’s naturalists all read, and 
ultimately accepted my book, as I have heard from the English and the 
Swiss, and while thirty million or more soldiers are practicing it to save 
their lives, the American naturalists mainly continue in ignorance even 
of what it is that I state. Because I naturally dwell on the tremendous 
evidence that this practically universal concealing effect of animals’ 
patterns is no accident, the American naturalist refuses to accept this 
inference and misses my ScrENtTIFIC Pornt. The artist’s science is that of 
the laws of visibility; and all the artists in the world will tell him that my 
scientific point, viz. that patterns on an object inevitably lessen its dis- 
tinguishability is straight goods. 
Add to this, nature is practically always doing these patterns in colors 
that counterfeit, beyond all human painter-power, one or another of the 
wearer’s typical backgrounds. 
Must one believe that the average American is so much less intellectual 
than Europeans that while those millions of soldiers are all protecting 
themselves with this vast concealing device, the American naturalist can 
not even see the absolutely antipodal difference between detecting an object 
and identifying it by its particular form of concealment-pattern after he 
has detected the object itself! 
Yours truly, 
AppoTtr H. THAYER. 
Monadnock, N. H., June 21, 1917. 
