GETTYSBURG, Pa. -- As dusk falls on the Triangular Field, where scores of Confederate and Union soldiers lay dead and dying on July 2, 1863, author Mark Nesbitt stands with a digital voice recorder and recites a series of questions.
We hear no response this Thursday evening. But when we turn the Panasonic RR-QR60 to playback, it appears that we had had a visitor.
"Thomas Lewis Ware," Nesbitt's voice says, "Are you here with us?"
What sounds like a gruff, short bark of "Yes" comes from the recorder.
One other question from Nesbitt seems to get an answer -- unintelligible, but definitely there.
I look around nervously to make sure no one's lurking nearby. Nesbitt, a former Gettysburg National Park Service ranger/historian who has written the Ghosts of Gettysburg books, smiles. This is very cool.
It's not the first time Nesbitt has recorded what believers say are the disembodied voices of long-dead soldiers called electronic voice phenomena, known as EVP. He and other ghost hunters claim their recordings are part of an evidentiary record of paranormal activity.
While skeptics wonder what sort of substances these folks have been smoking, ghost hunters say they're just average people discovering a realm that we of the 21st century have become too sophisticated to believe in.
Thousands haul digital voice recorders, camcorders, film and digital cameras, temperature and electromagnetic field detectors to haunted houses, cemeteries and battlefields to see, hear and occasionally speak to the dead.
Surf to ghost hunter Web sites and you'll find all sorts of paranormal phenomena: ghostly balls of light called orbs; red, white or blue clouds called ectoplasm; and sound files of voices from fields and cemeteries. On rare occasions, you'll find a photograph of an apparition as well.
Much of the evidence is highly interpretative. One ghost hunter's picture of hundreds of orbs is a cloud of dust to another. Some EVP sound like garbled static. And an ectoplasm with a face? Well, it might be exhaled breath.
"There are ghost hunters and ghost wanters, " says Chris Bravner, who recently took up the pursuit and joined the Pennsylvania Ghost Hunters Society.
The "wanters," he explains, see a ghost in everything.
Many ghost hunters say they're not out to prove that ghosts exist -- they're just having fun gathering evidence and showing people what they've photographed or recorded.
But it's all nonsense to Pat Linse, co-founder of the Skeptics Society, a national organization that rejects the paranormal and publishes a handbook for debunkers of myths called the Baloney Detection Kit. Linse, who at one time created photo-realistic illustrations, says the 1984 film Ghostbusters and its sequel reignited interest in ghost hunting.
She's particularly skeptical about using cameras to catch the spirits, noting that "Ghost photography started about the same time as photography."
Nor does she trust ghost hunters' claims from using other devices. She argues that they can be rigged to provide all kinds of feedback that can be misinterpreted as the supernatural.
Al Tyas, who runs D.C. Metro Area Ghost Watchers, believes that paranormal activity takes place but agrees with Linse that many ghost sightings have explanations in the natural world.
"A lot of times, it's not an entity at all," says Tyas, whose group will discreetly investigate a haunted home for free. "It could be anything from leaky pipes banging in wintertime to someone [taking] too much of their prescribed medication."
Rick Fisher, a Lancaster, Pa., resident and founder of the PGHS, says serious investigators actively try to rule out all ordinary explanations for what appears to be paranormal activity.
A pioneer in the use of digital cameras for ghost investigation, Fisher says he doesn't shoot in dusty conditions or when it's raining or snowing. He says he follows strict protocols for capturing data on cameras, camcorders and voice recorders.
Fisher, who lectures on paranormal activity and publishes a magazine on the supernatural, says he has nothing against psychics but works with them sparingly.
"A psychic can tell you that they're feeling something, but I can't verify that," he says.
So he, like many ghost hunters, relies on a variety of tools in addition to cameras and voice recorders such as:
Electromagnetic field (EMF) detectors ($35 to $150) to pick up ghostly energy.
Infrared temperature -- measuring devices ($70 to $150) to find cold spots in homes and other locations that might indicate the presence of ghosts.
Camcorders ($800 and up) that have the ability to shoot video at night. The ability to shoot infrared images is critical to some. Fisher discovered that by turning up the volume during playback of video, he could even find EVP.
Having the equipment is one thing; using it properly is another, ghost hunters warn -- one reason why newcomers should hook up with someone who has experience.