In an electric day of testimony that she hopes could make her a free woman, Jean Harris took the stand in her murder trial and told a packed courtroom her story of what happened the day she shot her lover.

In lacerating detail, she talked about deciding to commit suicide while at her home on the Maderia school grounds, of going out on her porch at twilight to test-fire her pistol. ("I was concerned with getting the gun loaded so I wouldn't play Russian Roulette with myself when I shot myself in the head.")

She talked about phoning Dr. Herman Tarnower, pleading with him to let her come see him ("Please,' I said, 'It's been a bad few weeks . . . .'") and being coolly allowed to come by. ("It would be more convenient if you came tomorrow," said the doctor, who was in fact having dinner with another woman, then, finally, "Suit yourself.")

She spoke about her thoughts as she made the five-hour drive from Virginia to Tarnower's home in Harrison, N.Y. First there was worry that she hadn't canceled politely to her dinner hosts. Then -- for the duration of the trip -- there was a "a feeling of peace knowing that I'd come to the end of the road."

Finally she addressed herself, at last, to the subject that made every member of the jury stare at her spellbound -- her story of what left Tarnower dying in his bedroom, shot in the arm, chest and back.

It was a story of a woman scorned and outraged, the story of a fierce lovers' quarrel. It ended, as Harris told it, with her attempt to shoot herself in the head, with her lover wresting the gun away from her at the last moment and being shot himself in the head. And then, there was the final battle -- the one that had yet to be described in this trial -- when Tarnower was shot again three times.

"He sort of stared at his hand for a while and went into the bathroom . . . I guess I didn't have a normal reaction. I couldn't believe it had happened. It used to be if he sounded hoarse, I'd insist he take a pill," said Harris, her face white, her expression fixed, as if reciting something she'd gone over many times in her memory.

"I started to follow him into the bathroom, but them I thought if I did it fast enough I could get it over with before he came into the room. . . . I couldn't find the gun . . . I got on my hands and knees and looked for it under the bed . . . . he came back and grabbed the gun and I said, 'Hi, please give me the gun or shoot me yourself.' . . . He said, 'Jesus, you're crazy, get away from me' and pushed me aside and picked up the phone . . . . I pulled myself up on his knees, the gun was on his lap, I remember reaching for it . . . . he dropped the phone and grabbed my waist, like he was trying to tackle me . . . I felt the muzzle of the gun in my stomach, or what I thought was the muzzle . . . I had the gun in my hand and it exploded again and it was such a loud shot and my first thought was, 'My God, that didn't hurt at all. . . . I should have done it a long time ago.'"

Subsequently, Harris testified, she tried shooting herself in the head again, hitting an empty chamber. Then she fired the gun out across the room in an effort to see what was wrong with it, hearing the gun go off again -- firing a bullet, she said, that she later learned had landed in the headboard of a bed. She said she had no memory of any other shots.

Former headmistress of the Madeira School in McLean, Va., Harris has been in court, since October, charged with second-degree murder in the shooting death of Tarnower.

The prosecution, noting that Tarnower had been seeing another woman -- and had been shot four times, including once in the back -- has called the shooting intentional, the act of a woman enraged. The defense has called the shooting a "tragic accident." Harris, suicidally depressed, drove to her lover's home to kill herself, defense lawyers say. How he had been shot four times had never been explained.

Today, her third day on the stand, a pale Harris, in a white blouse buttoned to the throat and fastened there with a pin, gave that explanation, beginning where she had left off Wednesday.

She was, as she told her story, nearly a textbook example of a depressed woman. The voice was strained, the tone exhausted. She spoke of the growing feelings of depression and exhaustion at Maderia which culminated the weekend before the shooting.

Harris tried to phone Tarnower throughout the weekend -- "it seems like it was all I did" -- and had trouble reaching him. She wrote one will that weekend, hid it hurriedly when visitors arrived, and could not remember where she had hid it. Monday, she wrote a will again, and got her papers in order. She also wrote a pained letter to the Maderia School board, including the phrase "I was a person and no one ever knew it."

She wrote a letter to her lover as well, the notorious Scarsdale letter, which has never been made public. It was obviously an unhappy letter, and Harris, who always took great pains not to express anger to her lover -- who, in fact, behaved through much of their relationship like a doormat -- was obviously distressed by it. "As soon as I mailed it, I regretted it," she said. "What I wanted was to be good company, and not be a whiner."

Monday, she felt she could not be good company anymore. She wanted to die, and testified that she wanted to drive to Tarnowner's house to see him one more time, to find that wonderful "peace" and "strength." She did not plan to tell him she planned to kill herself, she said.

She hugged her dogs, got in her car, drove the five hours arriving, finally, at the Tarnowner home, feeling "just as good" as she always did when she pulled in the driveway, though naively "surprised" that the lights had not been lit in anticipation of her arrival. The front door was locked. Undaunted, she entered the back way, "the way I entered anyway," and walked up the stairs to the doctor's bedroom, yelling, "Hi, Hi." He was barely awake when she arrived and not happy to see her.

"I said, 'I thought you'd leave the lamp on in the window, it's black as pitch,'" said Harris, of their conversation. "He was not enthralled to see me. He said, 'Jesus, it's the middle of the night.' I said, 'It's not the middle of the night.'

"He was lying on one pillow with another one held to his stomach and he closed his eyes and didn't seem to want to wake up. . . . I finally said, 'I've brought you some flowers'. . . . I waited . . . . then I said, 'Have you done any more work on your book?' He said, 'Jesus, Jean, shut up and go to bed.'

"I said, 'I can't go to bed and I'm just going to be a little while. . . .

I said, 'Won't you talk to me for just a little while?' . . . . He didn't but I didn't want to leave, I was just kind of hoping he would wake up and say, Jesus, that was a nutty thing to drive five hours to talk but now you're here, okay, what is it? . . ."

Tarnower did not wake up; he slept and at length Harris decided to go into an adjacent dressing room and find a shawl of hers that she intended to leave to her daughter-in-law, she testified. She pulled out the shawl and in doing so found a negligee belonging to another woman. Something snapped. She took it and walked with it into Tarnower's bedroom and threw it on the floor. He still didn't pay any attention, though she "thought he saw it land." Harris became angry.

"This time I felt the hurt and frustration," she said. "The script wasn't going the way I had expected it to . . . I had looked forward to seeing Hi one last time, I wanted to feel safe one more time with him, I thought that was reasonable. I picked up a box of curlers and threw them -- I didn't see where they went, and they broke a window. Hi heard the noise. . . . He came to the bathroom door and hit me across the face . . . I went back and threw something else. . . . he hit me a second time. . . ."

She became, says Harris, increasingly exhausted. "I just wanted to get dying over with," she says.

"I sat on the bed, I raised my face to him and said, 'Hit me again, Hi, make it hard enough for me to kill myself.'"

Tarnower said nothing. Harris walked away, picked up her pocketbook and took out her gun.

"Never mind, I'll do it myself," she testified she said. "I raised the gun and pulled the trigger and at the instant I raised the gun and pointed it at my head, I heard the gun explode -- it was a very loud noise -- and then I heard Hi say, 'Jesus Christ, look what you did.' and we both just stood there and looked at it."

The struggle ensued. The gun went off again -- the shot, Harris says, she thought was going to go through her stomach. Realizing she was not hurt, she ran away from Tarnower -- "so he couldn't stop me" -- and put the gun to her head.

"I took a very deep breath and pulled the trigger and the gun clicked," said Harris. "I'd gone to such great pains that that couldn't happen -- I looked at the gun and I was sure I had loaded it with six bullets, I thought I had a lot of bullets. . . . I pulled the trigger and it exploded again, and then I put it to my head and shot and shot and shot and it just clicked . . ."

Harris knew the servants would soon arrive, she said, and felt "panicked" about killing herself before they could stop her. She tried to unload and reload the gun, going into the bathroom and banging it against the tub. She ran back to the bedroom, where she saw Turnower trying to phone.

"I picked up the phone and heard nothing and I put it back down," she testified. "I said 'Hi, I think it's gone bad.' He said, 'You're probably right.' It was the only civil thing we said to each other all night . . . and it was the last thing I heard him say."

He leaned on her, she testified, and she helped him to the bed. ". . . I guess we were both in a state of shock." She heard the voice of the servants, Harris continued, and went to get help.En route, she saw the police car and returned. When they arrived at the house, she said, Henri [Van der Vreken], the servant "was hysterical, yelling 'she did it', 'she did it.'"