Time machines are supposed to exist only in science fiction, but on the Kennedy-for-President campaign right now it feels as if the candidate and his traveling retinue have flashed back in time to those few weeks last fall when he was the leader in the Democratic presidential race.

In the happy, confident demeanor of the candidate, the scornful taunting tone of his attacks on Jimmy Carter, the squealing, clutching crowds and the general hilarity of his entourage, there are unmistakable echoes of the Kennedy campaign before its slump.

The time warp is most noticeable, though, in Kennedy's stump speech. Campaigning here and in Kansas for Tuesday's primaries, Kennedy has been delivering generalized speeches about the American spirit -- like those he gave last autumn -- rather than the more specific format he adopted after his speech at Georgetown University late in January.

On one point, Kennedy is still specific -- his centerpiece proposal for immediate wage-price controls, and the candidate talks about it with great feeling.

"When Jimmy Carter decided to fight inflation by raising interest rates," Kennedy said in Wichita Saturday, "that meant wealthy individuals and corporations could invest their money at 19 percent and glide past inflation.

"But how about the consumer who can't borrow money and can't get the money to buy the things he needs? The only way, the only way, the only way to fight this fairly is to put on an immediate freeze and stop inflation in its tracks."

But the other domestic blockbuster of the Georgetown speech -- the call for gasoline rationing to cut consumption by 25 percent -- has disappeared from view. Kennedy hits the president's proposed 10 cent tax on gasoline forcefully, but almost never mentions his own rationing plan -- even when asked about energy conservation.

Foreign policy, a key part of Kennedy's message in the post-Georgetown days, has now been relegated to the status of an afterthought.

The candidate brings it up as one of "three last points" (along with gun control and women's rights) that he runs through at the end of his standard speech.

"I say this administration's foreign policy is a surprise foreign policy," he says in a tone that drips ridicule. "They were surprised in Cuba, they were surprised in Iran, they were surprised in Afghanistan and they say they were surprised by their own vote at the United Nations."

Meanwhile, some familiar old Kennedy lines have reappeared in the last week.

"Malaise" is back. A few days after the Iowa primary in January, Kennedy had stopped talking about Carter's speech last July when he suggested Americans are mired in malaise. Now, the candidte takes pains in every speech to mock the "malaise" notion and to note that he has a much more positive view of the American people.

From December to early February, candidate Kennedy regularly poked at Carter's refusal to campaign.But criticism of the "Rose Garden" strategy disappeared after opinion polls and primary elections suggested that the point was not going over.

In the past week, the Rose Garden strategy reappeared as one of Kennedy's chief targets.

Some Kennedy points have remained constant throughout the campaign. He has never stopped talking about the need for a federal health insurance plan for all Americans, or what he calls "the historic Democratic Party principles of fairness and equity," -- principles Kennedy says are violated by Carter's anti-inflation program.

One difference from the early days of the campaign is that Kennedy is a more consistent stump performer today. He still gets tongue-tied now and then, particularly in answering questions from his audiences, but on the whole he is a coherent, if not smooth, speaker.

As in the trips last fall, Kennedy's occasional oral slips immediately become running jokes for his entire entourage of staff, security men and press. b

In Wichita Saturday, someone in the audience asked Kennedy a question about the Seychelles Islands, a chain off the coast of Africa whose name is pronounced "Say-shells.'

In a prolix answer, Kennedy managed to twist the name around into "Seashells."

The reporters were all lined up at the door as Kennedy left to ask him a series of questions about "sea-shells." Kennedy laughed as loudly as anyone, then got the last laugh by challenging any reporter to name the capital of the Seychelles. No one could.

P.s. The answer is Victoria.