Plate XXIX. Photography 



The Milkweed pod in the upper left corner was photographed on a "backed" plate to counteract halation; the view 

 he right shows the same subject photographed without "backing." The yellow Narcissus to the left below was photo- 

 graphed on an isochromatic plate (without color screen); the same flower in the same lighting, made on an ordinary plate, 



