NEW YORK, DEC. 8 -- Blue-chip stocks rallied impressively in the last half-hour of trading today, with the Dow Jones industrial average jumping more than 56 points on a wave of futures-related buying.

After languishing throughout most of the session and even dipping into negative territory, the Dow average of 30 industrials ended the day up 56.20 points at 1868.37, a rise of 3.1 percent. That was the average's eighth-largest point gain and gave it a rise of more than 101 points in two days.

On foreign exchange markets, the dollar drifted lower against most major currencies today in light trading. Gold prices edged higher; Republic National Bank of New York quoted the metal at $482.90 a troy ounce at 4 p.m., up from $481 late Monday.

Analysts said foreign-exchange trading was quiet for the second day in a row as some traders closed their books for the year and others waited for U.S. trade figures due out Thursday.

In Tokyo, where the trading day begins, the dollar rose, closing at 132.78 yen. Later, in London, it dipped to 132.73 yen. In New York, the dollar was quoted at 132.64 yen in late trading, down from 132.985 late Monday.

On Wall Street, gainers outpaced losers by a 5 to 2 ratio on the New York Stock Exchange, with 1,142 stocks up, 465 down and 371 unchanged.

Analysts said futures buying triggered the big push upward in the Dow average. With less than 30 minutes to go, computer-guided futures programs kicked in to dump futures contracts and buy the underlying stocks.

"Futures are running this market," said Jack Barbanel, an analyst with Gruntal & Co. "I don't see anything fundamentally positive" that could account for the leap in equities prices.

Analysts were quick to characterize the rally as healthier than Monday's advance, which was confined mainly to the bluest of the blue chips. "There was breadth in {this} rally," said Philip Puccio, a senior vice president at Dillon, Read & Co.

In addition, Puccio noted that some institutional investors also went shopping for equities. That made the day's gain "a little better than a technical rally," he said.

Analysts like to see a rally accompanied by high volume and broad-based gains before they concede that an advance could be the harbinger of longer-term gains.

Big Board volume totaled 227.31 million shares, up sharply from 146.66 million on Monday, but 62.3 million of those shares involved purchases of just two stocks to lock in high-yield dividends, analysts noted.

Last week the Dow approached the lows hit during the October market drop. The big question this week was whether the market's key index would test the 1700 barrier.

There was considerable strength in oil companies, where Chevron was up 2 to 39 1/4, Exxon was up 2 1/4 to 39 7/8, and Texaco gained 3/4 to 33 5/8. Financier Carl Icahn said in a Securities and Exchange Commission filing that he might seek to increase his stake in Texaco to 25 percent.

Among other gaining blue-chip issues, IBM rose 2 to 111 1/2, Procter & Gamble jumped 3 3/4 to 83 3/4, Philip Morris rose 3 1/4 to 89 7/8, and United Technologies rose 2 1/8 to 32 3/4.

Losing issues included Federal Express, which lost 1 7/8 to 38 1/8, and Pan Am, down 1/8 to 3 1/2.

Nationwide turnover in NYSE-listed issues, including trades in those stocks on regional exchanges and in the over-the-counter market, totaled 259.54 million shares.

The NYSE index rose 3.19 to 131.42. Standard & Poor's index of 400 industrials rose 6.17 to 228.81, and S&P's 500-stock composite index was up 6.15 to 234.91.

At the American Stock Exchange, the market value index rose 3.54 to 236.57. The Nasdaq composite index for the over-the-counter market closed at 297.96, up 3.19.