Washington is full of strange and mysterious happenings which, for once, we can't blame on politicians, Last Halloween when I wrote an article for this magazine on English ghosts, the editors invited readers to submit their personal encounters with the supernatural. Unfortunately, there's not room to print all the letters we received.

Unlike Hollywood's cast of ghosts, the apparitions of local readers didn't hurl them around the room or turn them into demonic killers brandishing axes at their spouses. No blood burbled into the kitchen sink. No green slime oozed from the walls. Nonetheless, the encounters were frightening, and as is often the case, made many who experienced them doubt their sanity. THE TOP OF THE STAIRS

Soon after I moved to Washington in 1968, I had a recurring dream of a narrow staircase with a door at the top which was always closed. I would walk to the top of the stairs, but the door would never open.

In the fall of 1970, I went to work for an attorney who was handling the estate of an eccentric multimillionaire who had left his niece a deserted and run-down mansion called "Uplands" on Foxhall Road.

"Uplands" was unrentable due to severe water damage from the prior winter. The attorney asked if I would like to move in with a few friends to house-sit on a month-to-month basis. The estate's executors made minor repairs so house would be liveable.

I don't know the full history of the house, except that it was built in the late 1700s and was used as a hospital during the Civil War. The servant's with the door at the top which had been in my dreams for almost two years!

Soon after we moved in, several inexplicable experiences happened to us. A door shut tight on a male visitor and we had to take it off the hinges to get him out of the room -- the door would not close for the whole time we were living there. After we calmed him down, I noticed blood trickling down his arm. He went to wipe it away but there was no wound on his arm. The same exact incident happened to another friend a week later.

As the months went by, we became rather nonchalant about our unseen (but not unheard) permanent guest (or maybe guests). There were times when the chandelier in the foyer would start to tinkle and move back and forth. This was in the dead winter with absolutely no air currents going through the house. wWe would hear footsteps up in the servants' quarters on the third floor in a room that was jammed full of stored furniture -- one couldn't get into the room, much less walk around!

One night I was the first to come home from work. I was sitting in the library -- the front door was locked -- and someone walked right up the brick, wall, paused for a split second and walked right through the front door into the foyer. When I jumped up and ran into the foyer there was no one there and the front door was still locked shut.

Sometimes when I stop to think of what happened to us there, I have to really remind myself that it was true. Janice M. Mahon, Arlington. THE GRAY-HAIRED GHOST

While working as an apprentice carpenter in Georgetown, I had an experience in an old house we were remodeling. I had been left alone in the house to finish a number of small chores. I was repairing a door on the second floor when I heard footsteps upstairs. I didn't think much of this as I knew the owners had hired a maid to clean. My work was done on the second floor, I started to ascend the stairs to the third floor. Halfway up I began to feel a chill, like a feeling of fear in my back. It was broad daylight, perhaps 10 or 11 a.m., in August, and there was no rational explanation for this feeling. I looked into all the rooms expecting to find the maid somewhere. I asked aloud if anyone was home, but there was no reply. tThis seemed odd as the footsteps had been very distinct and the stairs were the only exit from the third floor. I went ahead into the bedroom that faced out towards the street to install some rope on a window weight. Suddenly the cold sensation of fear filled me again, only this time it was much stronger. I felt it was the spirit of an older gray-haired woman who was sorrowful and angry at me for disturbing her room and her house. I started singing and talking to myself to take the edge off this feeling, but it never left me. I rushed downstairs and decided to forget this. We returned to this house many times to complete our remodeling, but I never again felt afraid in that place. t

I do believe in supernatural events and "ghosts," but have no rationalization for their existence. Perhaps I am a silly nut. I have told other people about my experience and I suspect they believe I'm whacko. Jonathan Grubmeyer, Greenbelt. It takes courage to admit seeing a ghost in a society which prides itself on a ratinal explanation for everything. People fear that once they start believing in the "unexplainable" there is no end to the mental nonsense which can follow. Who knows, after ghosts it could be little green men from Mars. Mental institutions, after all, are full of people who hear strange noises or see things which aren't there.

The challenge for the medical profession, says Dr. Nichola Tauraso, who runs a holistic medical center in Frederick, Md., is to distinguish genuine psychic happenings like telepathy, precognition or seeing an apparition from serious psychotic conditions.

Psychic experiences are more common than we may think. What's more, some physicians say they are increasing because of what might be called "meditation backlash." "When people begin to open up their psychic windows, they have all sorts of experiences they don't know how to handle," says Tauraso, "but that doesn't mean the experiences aren't real, or that they are crazy." THE DARK SHADOW

The apartment my wife and I reside in was occupied by a single man prior to us. His name was Cornelious and he was proprietor of the Cornelious Printing Shop in Takoma Park. When he failed to appear at his shop for a few days and did not answer the telephone, the apartment manager broke down the door to the apartment. The bolts were locked from the outside. Cornelious was found dead and the apartment was almost a total wreck. Two months later, after it was repaird, we moved in.

In 1977 on a Thursday morning two weeks before the Christmas holiday, I took the elevator to the lobby where the secretary holds the paper for me. Upon reentering the apartment, I usually toss the paper on the couch and then enter the bedroom. As I was about to cross the hall, I was startled and stood almost petrified. Between the hall and the bedroom stood a very dark form. I hollered out to my wife, who was in the bed, if she was all right. The dark shadow made a turn to go into the bedroom, but immediately reversed and with a sliding motion speed down the hall toward the linen closet, turned left and entered the bathroom. I followed, clenching my fist. When I entered the bathroom, the black shape disappeared into thin air. Herman Magaziner, Silver Spring. The fear of ridicule, or of being considered a candidate for the nearest psychiatric clinic if you admit to seeing a ghost, is unfounded. According to a 1978 Gallup Poll, 51 percent of Americans accept

The idea of the supernatural, with one in nine claiming to have seen a ghost, Contrary to what might be expected, the more education you have, the more likely you are to believe in extrasensory perception. According to a 1974 Roper Poll, 68 percent of college graduates believe in ESP compared to 52 percent of high school graduates. In addition, twice as many people between the ages of 18 and 29 believe in ESP are those over 60.

The more educated "probably read more or are not so frightened to discuss something which in our culture is considered a sign of being crazy," says Dr. Karlis Osis, research director of the American Society for Psychical Research, which was founded in 1895 by William James, the father of American psychology, to bring scientific scrutiny to psychic phenomena. THE HUNTING ACCIDENT

Although I have had numerous encounters with the uncanny, none have been so dramatic as that of my mother, Margaret B. Martin of Appleton, Wis. Here it is in her words:

"Two weeks after my husband's unexpected death in September 1974, I had an unusual dream. I saw a corn field in late autumn. The stalks were dry and broken and the sky was a battleship gray. Two men in hunting jackets were walking through the field. Suddenly the smell of gunpowder overwhelmed me and I woke up. I told my sister Marie about the dream, but she passed it off as my being upset over my husband's death.

"A month later Marie and her husband invited me to drive out to our brother's farm. Their 16-year-old son Marty and a friend of his came along. While the adults visited, the boys took their .22s and went off to hunt squirrels. Less than an hour later, Marty's friend half-carried, half dragged him to the house. While crossing a corn field, Marty had stumbled and fallen. His rifle discharged and he was shot in the head. We rushed him to the community hospital where we were told they were not equipped for such injuries. Our only alternative was to race 30 miles to Appleton. I was near hysteria, when I remembered the dream. It gave me the strength to be strong for everyone else, and we made that trip with Marty's head in my lap. There was a happy ending. The bullet had bypassed his brain and he recovered."

Sheila Martin Sitterson, Sterling. THE DOGS

We lived in a rented house at Mogart's Beach, on the James River near Smithfield, Va., for about four years -- my husband, daughter, many cats and five dogs.

One night I woke to the sound of a large dog racing madly back and forth along the front of the house outside the bedroom window. It sounded like it was exhausted, panting and slavering. I didn't dare look out of the window because it sounded plainly and purely evil. The second time I heard it was a year or so later. My husband was very sich, so I fixed my bed on the living room floor. Again I woke to the same sound of the evil, gasping dog running back and forth. On the nights in question our dogs were all asleep in various parts of the house. Not one of them woke up. On both occasions there was no sign of a real dog outside -- no mud on the fence from climbing paws, no torn-up grass and dirt beneath the windows. It was the most wicked sound I ever heard. The area was once inhabited by Indians and was an area of early 17th-century colonial settlement.

Nancy G. Harding, Unionville, Va. THE FLOWERS

"Octogon House" is widely known as one of Washington's most haunted buildings. For four years I was repeatedly in and out of the place on business and once in a while to show it to out-of-town guests.

One of the legends has to do with the sweet smell of flowers occurring when the daughter of the orignal owner returns to her ghostly form. She killed herself, so the story goes, by leaping off the spiral staircase after a confrontation with her father about a love affair. A servant girl who had an unhappy affair with a military officer is said to have met death the same way.

One day I took my mother, sister and brother-in-law to see the house. We reached the old brick stairs which enter the garden, and my sister, who was walking ahead, stopped and said, "Neal, your're playing a trick on me. How did you manage to get that lovely odor in here?" By then the others and I had reached that spot and there was a pocket of strong, lovely aroma.

Another time we hired a photographer to do interior and exterior shots of the structure. When the prints were returned, one of them showed an ethereal, human-size white image at the back entrance of the house. Yet I did not see anyone in that area, nor did the photographer. Neal English, Arlington. Experts in the supernatural are convinced that people and animals do see ghosts. What causes them remains as much a mystery today as it did when Neanderthal man offered flowers to the spirits of his ancestors 100,000 years ago. The traditional explanation is that ghosts are earthbound entities who refuse to return to another world. The more scientific approach is to seek answers in complex theories of time warps or atmospheric imprints which obey yet undiscovered laws of nature. After all, the scientists argue, if someone claimed to have seen an airplane 200 years ago he would have been accused of hallucinating. The American Society of Psychical Research (5 West 73rd St., New York, New York. 10023) us currently categorizing different types of apparitions and is interested in hearing from people who have seen a ghost in the presence of at least one other person. Sooner or later, these researchers believe, they will understand ghosts.

Personally, I hope not. It's much more fun to retain that sense of mystery. What would Halloween be without it?