What was going on when I was born?

F OR almost two weeks, Gary Hart remained silent under Walter F. Mondale's repeated suggestions that Americans should not entrust the Presidency to a man as unknown, untested and perhaps unstable as Mr. Hart. Finally, on Thursday, Mr. Hart struck. ''He knows in his heart there is no blemish on my character that would prohibit me from governing this country in this decade,'' Mr. Hart said. Later that day, the Colorado Senator backtracked, saying he had been incorrectly told that the former Vice President was running commercials about the fact that Mr. Hart has changed his name, his date of birth and his signature. The curious incident underscored the extent to which the race for the Democratic Presidential nomination has become a contest in which the candidates' liabilities may be more important than their strengths. Strategists on both sides are bracing for a clash of negatives. Does Mr. Mondale, despite being propped up by endorsements and a seasoned staff, suffer from a chronic inability to stir the American people? Do the quirks in Mr. Hart's biography signify deeper problems of character and personality? That is what the candidates themselves are suggesting, as they exchange denigrations in what is, following last Tuesday's voting in 11 primaries and caucuses, more clearly a two-man race.

The republican terrorist who headed Ireland's most-wanted list was captured today after a shoot-out at dawn with 40 heavily armed detectives at an isolated cottage in the Irish Republic where he was holed up with three confederates. The St. Patrick's Day seizure of the terrorist, Dominic McGlinchey, known as Mad Dog because of his ruthlessness, came after a 90-minute gun battle during which one of the policemen was wounded in the shoulder. His apprehension was hailed by James Prior, Britain's Secretary of State for Northern Ireland, as a major victory in the struggle against terrorism. John Taylor, Northern Ireland's representative in the European Parliament, said that ''in the midst of all the meaningless rhetoric which we suffer from on this, our national day, this is the best news to come out of Dublin for many years.''

With 6 minutes 51 seconds remaining in the opening quarter last night, Bernard King was called for a rare foul: He was caught throwing an elbow at Mark Olberding. At the time of the call, King had scored only 2 points. The elbow the Knick captain threw was in retaliation for some rough treatment under the boards, and the incident seemed to make him more determined. King went on to score 36 more points that paved the way for a 123-109 victory over the Kansas City Kings at Madison Square Garden.

NEW HAVEN WHEN Yale's School of Organization and Management opened its doors in September 1976, Kingman Brewster Jr., then the university's president, presented it with its own coat of arms. The shield's abstract design depicted two conference tables - one gold, one silver - surrounded by dots of gold and silver. At the bottom was the motto ''Novus Ordo Seclorum'' - ''A New Order for the Ages.'' Yale's was not to be just another business school. This was to be a place where leaders would be trained for both the public and the private sectors - the gold and the silver - a place where the interaction of government and business would be stressed.

NEW ROCHELLE WILDCLIFF MUSEUM, once one of this city's premiere resources, attracting thousands of patrons yearly from the county and beyond, is about to be resurrected - not as a nature center, its original incarnation, but as an arts institution that will include a 150-seat theater. Last Tuesday night, by a vote of 4 to 1, the New Rochelle City Council approved a plan that would permit a nonprofit group, East Coast Arts, to convert the museum and to present such offerings as plays, readings, operas, concerts and dance programs. An art gallery will also be created.

Attorney General William French Smith met today with other Justice Department officials to consider whether to open an investigation into the financial dealings of the Presidential counselor, Edwin Meese 3d, who has been nominated to replace Mr. Smith. No decision was reached, and the matter will be discussed further, department officials said. According to the officials, the unusual Saturday meeting focused on the requirements of the Ethics in Government Act. The act says the Attorney General ''shall conduct'' a preliminary investigation, ''upon receiving information'' that a high-ranking Administration official might have violated Federal criminal law.

After months of emotional debate and millions of dollars in legal expenses, a tentative out-of-court settlement has been reached in a four-year- old Federal lawsuit seeking to integrate the public schools in Yonkers, officials said yesterday. The plan would attempt ''fully and faithfully'' to desegregate the city's racially divided school system over the next five years without mandatory busing. It would close some schools and create others with enriched programs to attract blacks and whites voluntarily into the same classrooms. ''This is a major opportunity to pull the city of Yonkers together and to move forward into a new era of community relations and financial health,'' Alexander Forger, a court appointed mediator, said yesterday in announcing the terms of the settlement. The settlement, worked out by lawyers for the Justice Department, the Yonkers branch of the National Association for the Advancement of Colored People and the Yonkers Board of Education, is subject to the approval of the Yonkers school board and City Council.

IN November 1981, Sanford N. McDonnell, who had recently taken over from his uncle as chairman of the McDonnell Douglas Corporation, received an unsolicited telephone call from James E. Worsham, an engineer with the folksy strains of rural Kentucky in his voice. Mr. Worsham, a vice president of the General Electric Company's Aircraft Engine Group, had become as skilled at selling the engines as he was at building them - and as a salesman he had a proposal for Mr. McDonnell. ''We were both going down to Melbourne,'' he recalls. ''Sandy was representing McDonnell Douglas on the sale of the F-18 to Australia, and I was representing General Electric. I called Sandy up and I proposed flying down together so we could integrate our proposals. By the time we got to Australia, we got integrated in something else.''

On a 10-acre parcel of land next to the 16th hole of the Hampshire Country Club in Mamaroneck, N.Y., a developer is building 54 town houses. The project, Fairway Green, is on Old Boston Post Road off Orienta Avenue.

NORWALK PERHAPS this city's most endearing legend is that when Yankee Doodle went to town riding on his pony, he did so from Norwalk, more than two centuries ago. As with many legends, though, there is no proof that Thomas Fitch 5th of Norwalk was indeed the Yankee Doodle on which the lyrics of an ancient British tune were based and which eventually became Connecticut's official state song. Nevertheless, the legend has persisted and it has a number of manifestations in Norwalk. For example, there is the Yankee Doodle Bridge on the Connecticut Turnpike, the Yankee Doodle municipal parking garage in the downtown business district and a street named Yankee Doodle Court. According to the legend, Mr. Fitch, the son of a Connecticut colonial governor, led a group of Norwalk men on horseback to Fort Crailo in Rensselaer, N.Y., in the 1750's to help British regulars during the French and Indian War. Before they left Norwalk, legend has it that Mr. Fitch's 16-year-old sister, Elizabeth, gathered up some feathers from the family chicken coop and stuck them in the men's caps. When they arrived at Fort Crailo, the motley appearance of the group is said to have prompted a British army surgeon, known only as Dr. Shuckberg, to compose the lyrics that included the line, ''Stuck a feather in his cap and called him macaroni.'' Macaroni is a British term for a dandy or fop.

U.S. Policies Anger Hussein Jordan's King Hussein hasn't had much cause for joy since he declared war on Israel in 1967 and quickly lost East Jerusalem and the West Bank. But last week, he seemed unusually gloomy.

PRINCETON AT SOME schools, undergraduates call them ''micks,'' for ''Mickey Mouse courses,'' and some call them ''cush courses,'' but most often they're ''guts'' or ''gut courses,'' which the Random House Dictionary defines as college courses ''requiring little effort.'' Students do not come to Princeton University looking for an easy course load, and guts at Princeton may be guts only relatively speaking. Often, the courses may be light on traditional examinations and paper work, but still involve difficult concepts or creative projects that can be as time-consuming as examinations and papers. Students, administrators and teachers agree, however, that such classes can ease the burden of otherwise heavy loads that include such ''killer'' courses as organic chemistry (dreaded by premedical students as ''orgo'') or Constitutional interpretation (the ''orgo'' of pre-law students).