Next winter when it is frozen over, go to that pond and stretch a twine from side to side. If you could stretch that line without any “sag” you would find that it would touch the ice in the centre and be four inches above it at each end.
Or go there some night in the summer and place a bright light at the water’s edge on one side of the pond. Then go to the other side, get into the water till your eye is just above the surface and endeavor to see the light. You don’t see it—because the rotundity of the earth prevents.
Now if you are building a church or a large hall, apply this principle of the curvature of the earth. Instead of making your floor perfectly flat make it swell up a little in the centre and sweep from this centre outward, toward the corners and sides. Then make your roof, pillars, and everything else in the place, and also the broad steps on the outside, curve in the same way and you will be imitating the Greek artists of the time of Pericles and Phidias. They may be said to have had level heads, those Greeks, when they abandoned the level and adopted the curve.
Enough of this.
