Richard Campbell, age 12, Fredericton, N.B., for his question:

Does the moon's gravity affect the land?

This is a thoughtful question. For the gravity of the moon pulls at the land and water surfaces of the Garth with equal force. On the oceans this causes the tides which rise sever a1 fact high twice every 21.E hours. But water is liquid. Each drop is able to move on its own. But the land is solid. It is rigid because the particles of which its rocks are made are firmly cemented together. Water is far more easy to move than solid material.

We cannot expect the solid land to heave up and down in tides like the liquid oceans. Nevertheless, the land does respond to the pull of the moon,: The entire solid globe moves as a unit. However, the tidal movement of the solid land is so slight that only the finest of fine instruments can detect it at all.