The Dying Fish
Cut a piece of deal into a prism about four inches long, and color two of the sides black or dark blue, painting the remaining side white. Sharpen one end into a small triangular point, and paint two eyes and a mouth thereon, so that the completed figure appears as in [Fig. 17].
Now, if you put this in a basin of water very heavily salted, you will find that the fish floats quite naturally, as in [Fig. 18], whilst if you place him in a basin of plain fresh water, he will immediately turn on his back and float dead, with the white side uppermost, as in [Fig. 18a].
Fig. 17.—Completed figure of fish.
Fig. 18.—“Dead” fish floating.
Fig. 18a.—Fish on his back.
This is caused by the greater density of the salt water acting upon the prism.
Fig. 19.—Showing egg hanging on wire.