Editor, Gazette-Journal:

The essential difference between glaciers and icebergs has escaped a few of us, as evidenced by the May 3 letter: "Simple experiment refutes sea level rise." Glaciers are ice resting on land, while icebergs float on the water. One can observe the effects of this difference using the exact same experiment by noting the level of the water in the glass just before adding the few ice cubes. As discovered by Archimedes over 2200 years ago, you will see the level rise as the ice is added. Eureka! Sea level rise defended!

David Forrest

Gloucester Point, Va.