The second time amateur archaeologists Craig Howell and Melody Carver climbed the weed-and-scrub-covered hillside near Chinatown, they knew they were close.
The old maps told them that the Zanja Madre - the "mother ditch" that brought water to the thirsty little Pueblo of Los Angeles more than two centuries ago - should be there. Then, standing between a graffiti-splattered wall above and the derelict expanse of an abandoned rail yard below, they noticed something they hadn't seen before.
There, exposed by the winter rains, lay four curved courses of old bricks. They'd found it.
For Ms. Carver, a nurse, and Mr. Howell, a former construction millwright turned Hollywood propmaker, it was a great find. It was a long-lost artifact that harked back to the days when Los Angeles was a Mexican settlement and the water manager was more important than the mayor.
But it also was a reminder of the role that amateur scientists play in scientific discovery. Even as some part-time enthusiasts find their access to important equipment dwindling, they remain an invaluable resource.
Indeed, over the years amateurs have made significant contributions to such widely diverse fields as ornithology, mathematics, and astronomy.
*Hedy Lamar, most commonly remembered as the first actress to appear nude in a major feature film, discovered "frequency hopping" in the early 1940s. First used in antijamming technology during World War II, it later became integral to the development of cellphones.
*Laura Nickel and Landon Curt Noll, California high-schoolers, in 1978 discovered the 25th Mersenne prime - the largest prime number then known.
*Elliott Coues, an Army physician during the mid-1800s, wrote a pioneering study on the classification of North American birds.
*Marjorie Rice, a San Diego housewife and mother, worked out previously unknown geometric shapes and patterns after reading a Scientific American column in the mid-1970s.
In some cases, amateurs have the time to do what paid professionals can't.
"Some of these people actually have more freedom to go out and collect than a professional who has a full-time job with teaching, research and professional commitments," says Sam McLeod of Los Angeles County's Natural History Museum.
Howell certainly thinks that's the case with his work. "I have time to sit down and study things. My next meal doesn't depend on how rapidly I do the work," says Howell. "While [professionals] have multiples of hours and days, I have multiples of years."
As with many scientists, the roots of Howell's investigative passion can be traced to his youth. Back when he was a boy, his father's idea of a family outing was to bring the kids along while he ferreted out old hydroelectric plants. A metalworker, Howell's father was fascinated by public-utility infrastructure - generating stations, gas, and waterworks.
Later, Howell's own interest manifested itself in travel to all 50 states and such far-flung countries as Russia and Nepal to study public utilities.
His fascination even extends into his investments. Playing off "The Honeymooners," "Cramden bonds" are investments in transportation companies, and "Norton bonds" are investments in sewers and other utilities.
His formal training in archaeology came in the early 1980s, when Howell studied at the California State University in Northridge Archeological Research Center. Back then, it was a program open to the general public as well as academic specialists.
That was followed by a couple of years helping out at a dig at the Plaza Church in Los Angeles's historic Olvera Street district.
To him, the importance of archaeology "isn't about finding bones or obelisks," but about answering fundamental questions about the people who once used the artifacts: "How did they do things? What did they eat?"
The impact of amateurs can be profound. The American Society of Vertebrate Paleontologists, for example, gives out an award to amateurs who make "outstanding and sustained contributions."
Tough keeping up
But in some fields, it's getting harder for nonprofessionals to keep up, as science becomes increasingly reliant on costly and delicate instrumentation. Amateur physicists don't have access to particle accelerators, and a number of biological science sub-specialties like taxonomy rely more and more on DNA studies.
"It is very difficult now [for amateurs] to contribute ... except in the observational sciences," says Arthur Molella, director of the Smithsonian Institution's Lemelson Center For the Study of Invention and Innovation.
Recreational stargazers aren't likely to get time on the Hubble Telescope, but recent advances in widely available technology have meant amateurs still play a role. "What was a cutting edge instrument 25 years ago can now be found in the back yard," says Mark Rothenberg, a historian of science at the Smithsonian.
(c) Copyright 2000. The Christian Science Publishing Society