Many people would like to forget what happened to them in this gambling city by the sea. Richard Cade wishes he could remember.

"Everybody says it was a tough fight," said the 243-pound heavyweight from Salina, Kan. "I don't remember anything after the second knockdown."

Cade hit the canvas four times in a scheduled eight-round Thursday night cofeature at the Sands Hotel and Casino. Tony (TNT) Tucker of Detroit dropped him once in each of the third, fourth, fifth and sixth rounds. The ring physician wouldn't let the bleary-eyed Cade answer the bell after that.

"It was my first time on television," said Cade as he recovered in a carpeted dressing room. "I didn't look too bad, did I?"

"Nah," said his trainer, "you got up off the deck four times."

"Geez," said Cade, 28, "was it four times?"

The plush red banquettes in the Sands headliner auditorium were filled with 850 people who sipped cocktails and cheered as Cade took his lumps. The klieg lights of the ESPN cable TV network throbbed down on the blue ring. The ring girls wore skimpy silver suits advertising a diesel engine.

When Cade made his last, lunging bid at the handsome Tucker, whose hair cascades in shiny ringlets down his back, someone shouted, "Hit him in the hair."

In the hallway under dazzling chandeliers were a stretcher and a large fisherman's tackle box. On the top of the box the word "TRAUMA" was printed in black ink.

Another night on the beach.

Atlantic City has emerged in a scant four years as the boxing capital of the East. Many say it is becoming the boxing capital of the world. Last year there were 49 fight programs in the nine casinos scattered along the boardwalk here. This year the state boxing commission expects twice as many.

The increase should put Atlantic City well ahead of New York State, where there were 75 boxing shows last year, and about even with Las Vegas, where there were just over 100.

Pro boxing's success here and in Las Vegas proves again how the sweet science and gambling go together. In a way it's bad because it demeans the most demanding and unforgiving of sports. In another way, and in the eyes of the athletes, it is good because without the gilt and glitter of the gambling scene there would be less work.

In Atlantic City there is work aplenty--sometimes a different card every night of the week.

The Cade-Tucker matchup was a prelude to the "ESPN middeweight championship" bout between Jerry Holly of Orlando, Fla., and Tony Nelson of Braddock, Pa. Nelson and Holly are what used to be called good club fighters, but Atlantic City and cable TV want names and titles, not club fights.

So today Nelson is ESPN middleweight champion by virtue of an 11th-round technical knockout over Holly, the referee stopping the fight as Nelson pounded away at his taller foe. The TV people gave Nelson a paper crown and sent him leaping around the ring as the cameras ground away.

On July 22 another good club fighter, Robert (Boo-Boo) Sawyer of Washington, D.C., will fight for the ESPN welterweight title. The professional ring record of this potential champion is 9-5.

That it is a bogus title matters not to Sawyer, who calls the ESPN crown, "The biggest opportunity of my life. I want it and I'm going to get it. It's like somebody took my mother's wallet and I'm searching for him to get it back."

Formal betting on the outcome of bouts is not permitted in Atlantic City, where the state gambling commission holds a tight rein on casino activities. Nonetheless, boxing took off like a brush fire when gambling was legalized and the casinos opened in 1978.

The first casino boxing program was put together that year by Frank Gelb, who remains a kingpin of the Atlantic City fight scene. Over breakfast he explained how boxing, television and the casinos feed each other.

The primary concern of the casinos is to attract gambling "traffic," particularly high-rollers who drop big money at the gambling tables, said Gelb. Knowing how boxing appeals to gamblers, the casinos use the lure by sending out engraved invitations offering their most credit-worthy customers free tickets, rooms and meals to fight nights.

At the Sands on Thursday, "more than half the seats were comped (given away on free tickets)," said Gelb. The casinos keep records of their gaming table "drop" and can predict the effect of a boxing show and the high-rollers who attend it on the total wagered. They won't release the figures, but the increasing number of boxing shows indicates the numbers are positive.

Television, particularly cable, further feeds the boxing machine with its incessant demand for live sports. And television answers the publicity needs of the casinos by spreading their names nationwide.

It all spells work for boxers and happiness for promoters like Gelb. In a noncasino setting he'd have to worry about attracting paying customers to an arena to recoup expenses and make a profit. But the casinos pay him to bring in a show, and provide the facilities and room and board for the fighters. The television networks or cable operators pay, too, so Gelb has made his costs and profit before anyone walks through the door.

Gelb said the arrangement puts a special responsibility on him to provide good shows because a bad one reflects on the network or the casino, which treasure their public images above all else. "People don't say, 'Frank Gelb put on a lousy show last night.' They blame it on the Sands or ESPN."

He said his greatest difficulty is in finding quality fighters to fill the increasing demand. He and other promoters have solved the dilemma in part by bringing in fighters from the Midwest and even the West Coast. Thus Cade, from Kansas, and Tucker, from Detroit, meet in an eight-rounder in New Jersey.

Last winter the Tropicana, the newest Atlantic City casino, announced it would present boxing every Tuesday night. It has done so, successfully, to the astonishment of many experts. Said Bob Lee, assistant commissioner of the state boxing commission, "One of my big concerns with the weekly program was that the quality of boxing might deteriorate. There is nothing worse than putting on garbage shows.

"But because boxing interest has skyrocketed with Muhammad Ali and then the 1976 Olympics, more gyms have opened and there are more good fighters available, particularly in the Midwest. I was the first one to worry. The Tropicana had a hard time convincing me and I wasn't convinced. But I am now. I have no problem with the fights we're getting."

Don Elbaum, who copromotes the Tropicana shows, said the hotel auditorium has been filled for all but three of the weekly shows, management is delighted with the results at the casino tables and he's working on a TV deal to sweeten the pot further. "The feeling here is like fight night at the old St. Nicholas Arena," he said.

Four blocks down the Boardwalk from the Tropicana, Davey Moore, the World Boxing Association junior middleweight champion, spars publicly every day in a ring set up on the sand in preparation for his July 17 title defense at Bally's against Ayub Kalule.

"They bring me down here to train to get away from the distractions," says Moore, 22, gesturing toward women strolling by in bikinis. "I don't care. I could train on the moon. When you want to hold your title there isn't any distraction."

It's hot and steamy on the sand. Moore spars with Robert Sawyer and Darryl Smith, also of Washington. Then he skips rope. He does 106 situps, 50 pushups.

Sweat pours off him. "Got to go to the room," says Moore, and leads a merry chase through the clattering glitter of the casino at Bally's, up the elevator, into the cool silence of the 16th-floor room that has been home for a month.

Atlantic City, says Moore, "is the East Coast mecca of boxing. Las Vegas has the biggest fights, but Atlantic City will surpass them because they have so many fights."

It is good news for young boxers like him, said Moore, whose title defense will be only his 11th pro fight. "It's more work for boxers. A lot of guys used to go out maybe two or three times a year. Now they might get seven or eight fights. It increases employment."

As he talks, the champion from the South Bronx strips off layers of soaked sweatclothes and lays them neatly on the edge of the open window to dry, tenement style.

And somewhere in the marshland behind the beach a plane takes off, bearing Richard Cade on the first leg of his journey back to Kansas, carrying with him his $750 earnings and his interrupted memories.