..and school children were busy standing eggs on end !
I think this happens *twice* a year, at the spring *and* the autumn equinox. From what I've heard, because the Earth's axis is perpendicular to the plane of its orbit around the sun, not only is the length of day north and south equal, but so is the gravitational pull of the sun. Of course...
... Eggs on end during the equinox: how do these things get started?
Perhaps it was the school children who started it.
[Y]ou can balance an egg, or not, any old time.
I once heard a story that, faced with this problem at some other time of year, Columbus thought a while, then brought the egg down kind of hard on its end. It worked.
Another nice thing about eggs is their architecture. Try to break one in your hand by squeezing it end to end. It was once reported in Scientific American that eggs are so strong you can drop a gross onto a lawn from a helicopter hovering at a decent height, and only one or two will break. At the same time, the shell is permeable to gas during incubation, and delicate enough that the chick can hatch.
