_Color Mixing._ You probably know something about color and the mixing of colors. However, you may find the following directions helpful. First let us experiment with yellow. If you add a very little bit of blue to the yellow you can see the yellow turning to greenish-yellow. As you gradually add more blue you can see the greenish-yellow turning to yellow-green and finally to green. Let us begin again with pure yellow. If you add a very little bit of red to the yellow you can see the yellow turning to orange-yellow. As you gradually add more red, you can see the orange-yellow turning to yellow-orange and finally to orange. Let us begin once more with pure yellow. If you add a very little bit of blue and red to the yellow, you can see the yellow turning to a grayish-yellow. As you gradually add more blue and red you can see the grayish-yellow turning to yellowish-gray, and finally turning to a neutral gray. Let us experiment with red. If you add a little bit of yellow to the red you can see the red turning to yellowish-red. As you gradually add more you can see the yellowish-red turning to reddish-orange, and finally to orange. Let us begin again with pure red. If you add a very little bit of blue to the red you can see the red turning to a bluish-red. As you gradually add more blue you can see the bluish-red turning to reddish-purple and finally to purple. Let us begin once more with pure red. If you add a very little bit of yellow and blue to the red you can see the red turning to a grayish-red. As you gradually add more yellow and blue you can see the grayish-red turning to reddish-gray and finally turning to a neutral gray. Let us experiment with blue. If you add a little bit of yellow to the blue you can see the blue turning to greenish-blue. As you gradually add more yellow you can see the greenish-blue turning to bluish-green and finally to green. Let us begin again with pure blue. If you add a very little bit of red to the blue you can see the blue turning to a reddish-blue. As you gradually add more red you can see the reddish-blue turning to bluish-purple and finally to purple. Let us begin once more with pure blue. If you add a very little bit of yellow and red to the blue you can see the blue turning to a grayish-blue. As you gradually add more yellow and red you can see the grayish-blue turning to bluish-gray and finally turning to a neutral gray. Brown, which is not a pure color, is made by adding a little blue to orange. There are yellow-browns and red-browns, but some blue is used in making every one of them.