He tries to vary the subjects of the column, from topics such as birdwatching to how to measure an insect's heartbeat.

Occasionally, SAS sells hard-to obtain products that are necessary for the projects in the column to amateurs, which gives a crude estimate of the number of people who are attempting the projects described. The most popular column demonstrated the phenomenon of audio illusions, which are roughly analogous to their visual counterparts; 700 copies were sold.

Carlson has just finished compiling a compact disk with all of the Amateur Scientist columns that have been written since the inception of the series as "The Backyard Astronomer" in 1928. He estimates that he sells 20 copies a day by mail order, and predicts an enormous expansion in sales when the product is picked up by the Ingram Book Group, a major distributor, later this year.

Looney Tunes

Carlson says that while there are many smart and serious amateur scientists in America, there are just as many crazy people with delusions of scientific greatness.

"When most people thing of amateurs they think of their nut file," he says. "Every scientist has a file filled with letters from people with the latest theory of space-time and God and creation that think they're the new Galileo."

Indeed, Carlson has made refuting pseudoscience something of a hobby. He has been involved in a number of research projects that aim to debunk astrologists' claims, including one that was published in the journal Nature in 1985.

He says he can't tell whether some of the oddest research proposals that he receives are serious or intended as parodies.