It is a pleasant September afternoon on Clopper Lake, a 90-acre expanse of water in Seneca Creek State Park in Gaithersburg. Blue herons pose on the shoreline. A turtle rests on a log.

Sgt. Susan Hatter, a state park ranger, pilots her patrol boat along the lake's edges, peering across the water. After nearly an hour, something catches her eye. She idles the boat near the gray, leafless branches of a dead tree that has fallen into the lake.

"We found another bottle," she says into her radio.

The glass is clear; the outside is wrapped in black thread and has no label. Inside, dangling from the cork by the thread, is what looks like a postcard cut in the shape of a hand. It is made from two photographs stuck together; one side depicts a palm, the other side the back of a hand. The back is affixed with antique stamps and an "air mail" sticker. A broken skeleton key is tied to the base of the hand.

Since May, park employees have found nine such bottles, each subtly different from the others. All have fortune-cookie-from-the-dark-side messages printed on the palms of the postcards. The one Hatter found says: YOUR QUESTION IS A MISUNDERSTOOD ANSWER.

The author of the works says they are the communications of a "reluctant oracle" -- a term that describes the artist himself. He calls himself Hobby Horse and will not divulge his name or other details, other than to say he leads "a normal life." To prove he is the artist, he encloses digital images with his e-mails that depict the hand that appears in the bottles.

In one of his e-mails, he cites "The Blair Witch Project" as a "contemporary recasting of the horror novel." The 1999 movie was partly filmed in Seneca Creek State Park. He also mentions Edgar Allan Poe, who published a story called "MS. Found in Bottle," as the inventor of the detective story. "Imagining this art project and developing it felt similar to writing a detective novel -- without the last chapter."

The form is a cliche: a message in a bottle. But people who have seen Hobby Horse's artworks find them creepy and alluring. The idea of a disembodied hand is less than pleasing. Some of the palms contain splotches of red that could be taken for blood. The thread that suspends each postcard has been stitched along the side of the middle finger.

Hatter keeps the bottles in the park office as she investigates their meaning and origin. They strike her more as art than crime. "From our point of view, there's nothing threatening about them," she says.

Still, the puzzle they present is intriguing. "It's unanswerable; it's very daunting," Hatter says. "It drives me insane when I put my head to it. But I appreciate it. I would like to find out more, but I'm not sure we ever will."

One feature the postcards share is the stamp "REBUTS." A French postal term, it means dead letter.

Sometime in late July, a package arrives in the office of the Washington City Paper. Taped to the box's top is a piece of paper with the sentence: "One of several postcards (?) found this year floating in bottles near the Clopper Lake boathouse." It is signed "M. Antipyrine." The package includes an e-mail address.

Inside the box is one of the bottles, and inside the bottle is a hand-shaped postcard. The palm reads: SEEK INSTEAD THE QUESTIONS TO YOUR ANSWERS. City Paper runs a photo of the bottle as its "Found Art" feature Aug. 13.

On Aug. 26, an e-mail from a Washington Post reporter to M. Antipyrine -- sent to the address provided to City Paper -- yields a reply in less than 10 hours. "Sorry," it reads, "I would rather not contribute to a story about" the bottles. But he offers to forward a message to the artist.

M. Antipyrine also provides his real name on the condition that it not be published, saying that he received "heated e-mails" after the bottle appeared in the City Paper. "[S]ome of the people involved in this are a bit peculiar," he writes.

Two days later, Hobby Horse replies to the query. He has "one concern," he writes. "I need your assurance that you will not share any information you learn about my identity."

Hobby Horse ignores a request for a meeting. But during an e-mail exchange last month, he sends a photograph of a hand that matches the one depicted in the postcards, providing some evidence that he is the artist.

In mid-September, Kerry Mc Aleer-Keeler, a printmaking instructor at the Corcoran College of Art and Design, scrutinizes one of the bottles. She uses similar motifs -- hands, keys, postage stamps -- in the "book art structures" she fashions.

"It's puzzling and I guess that's good, because it makes you want to know more about the piece," she says. She suggests that the hands might symbolize humanity, that the antique stamps -- most of them from Romania, some from Cuba and Taiwan -- might refer to history, that the bottle and the thread might signify containment or bondage.

She ponders the pieces of skeleton keys attached to the base of the hand, to a finger, to the outside of the bottle. "The fact that the key is broken is kind of pessimistic," she says.

And then there is how the work has been displayed. "I'm wondering if it's a joke to the artist that everyone is struggling to figure it out," she says. A "wonderful marketeer" may be behind the bottles, she adds. "It's hard for artists to find ways to show their work. Sometimes you have to get creative."

Even so, the bottle she holds in her hands has an eerie quality, McAleer-Keeler concludes. "It's definitely strange. It's definitely mysterious."

In late September, Hobby Horse's e-mailing provides a detailed explanation of the bottles: "Deciding what would go into each bottle was like designing a scene. What evidence to expose? What to hide? How to show clues with ambiguous meanings? How to display an airtight half-told tale?

"Allowing the pieces to be discovered created more possibilities for imagining the full story and/or participating in it. The finder can view me as provocateur or polluter; artist or criminal. It enabled me to find an audience that was not self-selected and introduce an artifact into a stranger's life that might seem as though it fell from a place not quite here. . . .

"When I started the work I did not try to make sense of it. But after a month or so I began to recall one of my earliest memories -- learning how to read. I know that I actually learned how to read at school but what I remember is learning how to read at church.

"For a straight year in Sunday School we had to write down a prayer during the week and read it on Sunday to the class during prayer time. I don't remember any of the prayers I wrote or read. But as I became literate that year, I do remember a feeling of unfulfillment. Perhaps I learned something else that year too.

"Anyway, maybe in some way this work is a belated attempt by an agnostic father to respond to the 52 prayers of the boy inside who still wants to believe. (Or maybe I just have too much time on my hands.)"

The postcards all bear a poem on the back of the hand, in the place where an address would appear. Each version is similar to the others and at the same time unique. In this one, abbreviations have been spelled out, missing letters filled in, and three French words translated into English:

Dreaming, he remembers

Awake, he writes the [question] on his palm

Dreaming, he read[s the] answer he holds

Awake, you [discover] his [recreated hand]

Dreaming, you find the quest[ion] he grasps

Awake, you forget.

Nine bottles containing hand-shaped postcards have been found at Clopper Lake in Maryland's Seneca Creek State Park. "I would like to find out more, but I'm not sure we ever will," Sgt. Susan Hatter, a state park ranger, says of the messages found inside bottles at Clopper Lake. Hatter says the works strike her more as art than crime.