M. Buffon, a good many years ago, made a very interesting discovery, which is practically very useful, and very closely approaches in correctness the diagram principle in determining the colors which contrast. He discovered that if a wafer be placed on a white sheet of paper, and gazed steadily at for a few seconds, and then the eye removed to another part of the paper, a spectrum of the same size as the wafer and of its contrasting color is seen. The spectra are, however, rendered more distinct when the wafers are looked at on a dark ground, and the eye then directed to a white ground. This simple fact is the reason why black printing is more comfortably and easily read on a white ground than red, for red would have a contrasting green spectrum floating before the eye on a white ground; white being the contrast to black, the spectrum is prevented in such a combination. By this simple process, as well as by the aid of the diagram, the colors at the disposal of the flower gardener can he arranged according to the law of contrast.

The following is a table of the colors and their contrasts:

Black........

White.

White........

. Black.

Red..........

Green.

Orange.......

. Blue.

Yellow.......

. Indigo.

Green .

Reddish Violet.

Blue...

Orange.

Indigo.,

Orange Yellow.

Violet..

Bluish Green.