Lise Mitchell, age 10, of Houston, Texas, for her question:

What is a Mercator's man?

A map should show its proper place on the globe and this requires a network of numbered lines of latitude and longitude. The map and the grid work of lines together form a projection. A mercator projection shows equal distances between the parallel circles of latitude, which is accurate. But it also allocates equal distances between the longitudes    and this is inaccurate. The meridians of longitude taper from their widest separations at the equator and meet each other at the poles. The mercator projection gives a neat, flat map of the globe. But its east west distances are distorted.

Countries near the equator; where the latitudes and longitudes are about equal, are accurately projected. Distortions increase in higher latitudes where narrow areas are stretched to fit the wider longitudes at the equator. Small islands in the Arctic are portrayed much bigger than their actual size. And Greenland looks big enough to be a continent    which it is not. Several other grids have been in¬vented to show more accurate map projections. One of these shows the globe sliced into curved sections that link at the equator and taper towards the poles.