Treasury Secretary W. Michael Blumenthal, arrived here for talks on the world economy as the U.S. dollar fell to record postwar lows in West Germany, Switzerland and Japan.

As he arrived here, the city of his birth, the dollar opened at a new low of 224-15 marks.

When asked by West German reporters why the U.S. had not bought dollars on the world currency markets in order to support it, Blumenthal said, "We do intervene, of course to counteract disorderly movements."

He added that "beyond that, we are in a system of flexible exchange rates that reflect basic forces of the economy . . . We think that given the basic strength of the world's largest free economy, we are quite sure that the strength and stability of the dollar is assured . . . We have no interest at all in the depreciation of the dollar."

Blumenthal, on the final leg of a seven-nation tour to meet with finance ministers on energy and international money matters, was greeted at a guarded military section of Tegel Airport by Mayor Deitrich Stobbe, U.S. Ambasador in Bonn Walter Stoessel and the allied military commanders.

In hectic foreign exchange trading yesterday, the British pound gained slightly on its second day of freedom from Bank of England restraints and the price of gold rose in both London and Zurich, Europe's major bullion-trading centers.

Foreign exchange dealers said the dollar's poor performance was related to trading in the British currency since Monday, when the pound was freed from its informal link with the dollar and rose more than six cents.

In Frankfurt, the dollar ended trading at 2.2388 marks, down from 2.2546 marks Monday and below the previous record low of 2.2490 marks July 26.

The dollar fell to a record low of 2.2170 Swiss francs at the end of trading in Zurich, down from 2.2352 Swiss francs Monday.

Nervous selling in Tokyo sent the dollar to 247.025 yen, compared with Monday's 250.325. The dollar now has dropped nearly 20 yen over the past month after holding steady above the [TEXT OMITTED FROM SOURCE]

In London, the pound reached $1.8640 in morning trading, up from $1.84 at Monday's close. But at midday, traders learned that Britain's National Union of Mineworkers had rejected a Labor government pay proposal linked to greater productivity and the pound started to fall. It closed just above Monday's late level of $1.84.

266-yen level.