In the winter of 1949, a stoop-shouldered geology professor being hunted by espionage agents took a stroll into the hills of Basel, Switzerland. While his wife and daughter grew frantic back at their hotel, he happily chipped away at boulders until long after dark, unaware that he was pointing the way to the "Chinese century."

The absent-minded geologist was Li Azu-kuang. By the end of his cloak-and-dagger journey across Europe and Southeast Asia, he had reached Peking, finishing his masterwork, "Distortion of Continental Asia," and laid the ground for his eventual Chinese-style canonization as an Einstein and Edison rolled into one. In flashes of insight that would enormously improve China's economic prospects, Li would shortly prove against great odds that vast reserves of oil lay under Chinese soil and he would inspire perhaps the most successful system ever devised for predicting devastating earthquakes.

Now, three decades after Li's journey, the Chinese have begun to say in editorials, broadcasts, movies and briefings that the next century is going to be theirs.

If they can make the transformation from great population to great power, scientist inside and outside China says, it will be in large part because of an approach to scientific inqury pioneered by Li. He promoted among his disciples an absolute singlemindedness in pursuing answers to pressing problems. Then he added a technique for using his nation's unexcelled historical records and for recruiting from among its 800 million people more amateur scientific observers than the richest American research foundation could ever afford.

As China's new leaders quietly close the era of Mao Tse-tung, when ideology was supreme, they have embraced Li's ideas and personal example as the most fitting symbol of what they intend to be a new era of scientific, economic and military power.

Chinese and Western scientists interviewed here and in the United States who are familiar with Li or his work say the approach he inspired may have considerable impact on scientific progress in the rest of the world as well. Using the thousands of amateur observers to predict earthquakes, for instance has been called by Frank Press of MIT, now President Carter's science adviser, "a highly original development that we may wish to copy."

Li was born in 1889, in the central province of Hupei. He ranked at the top of his classes in Chinese classics and then went off with many other bright young Chinese of his day to study engineering and shipbuilding in Japan. He returned to Hupei to teach in a technical school. The 1911 rebellion that overthrew the Ching Dynasty began in Wuhan, the huge river city where Li taught, and he reportedly played a small part.

After further study in England, he became a professor in geology at Peking University. The city that is now China's capital was controlled by local warlords in the 1920s and 1930s, but Li stayed away from politics to concentrate on his field.

Foreign geologists had been developing a picture of the earth's crust as great plates sliding majestically about, a few inches every decade, crashing into each other to lift up mountains, breaking apart to open up oceans. But these Western theorists tended to ignore China, or write it off as the continental mass between the Himalayas and the Pacific with few interesting features of its own.

Li spent his two decades tramping over the north China plain. Ignoring the struggle for power in China.

By 1948, while Li was still caught up in his mountains and valleys. The Communist Party was about to unite the country for the first time since the Ching Dynasty. Li was in England, attending an international geological congress. He lingered there until the situation in China settled down and his daughter completed studies at Birmingham.

A friend woke Li one night in 1949 with a telephone call. The defeated Nationalist Chinese government had cabled its ambassador in London to do whatever was necessary to convince Li he should disown the Communists.

Li packed his knapsack, hammer, compass and magnifying glass, his briefcase and the bulky manuscript of the book he was writing and got on a cargo vessel crossing the English Channel that night. His family joined him in Switzerland. They made a meandering journey home. Li tinkered with his manuscript and entertained himself comparing modern political troubles with the geological catastrophes he saw along the way.

Finally he reached Hong Kong and then Peking, where the new leaders of the People's Republic were wondering what happened to Li Szu-kuang.

Chou En-lai, the new Chinese premier, called on the scientist at the Peking Hotel. "We are preparing to call a national geological conference. We have waited five months for your return. Some people said Li Szu-kuang would not come back and that there was no point in waiting any longer. But I said, 'He's bound to come sooner or later.'"

Among several problems Chou wished to discuss was China's critical oil shortage. Buses in Peking were being propelled by natural gas bags.The Western economic embargo had cut off most other souces. Foreign experts said there was little chance of finding oil anywhere but in China's remote northwest, and even there production would not be very good.

Western scientist thought large underground oil pools could only have developed from ancient seabeds where dead plants and animals collected China had few such areas. But Li's theory of geomechanics indicated that at certain points, particulary in the Sung-Liao and north China plains, there had once been depressions that could have formed large lakes and supplied all the conditions for future underground oil. In 1959 oilworkers at a barren spot of Manchurian prairie called Taching, struggling under great hardships of weather and terrain, brought in a gusher. Other oil-rich areas at Shengli and Takang were discovered. Foreign experts began to talk of reserves rivaling the Middle East. China moved into a position where it could export oil to pay for the new equipment it needed for a modern industry and army.

In 1966, when Li was 77, a major earthquake hit Hopei Province. Casualties were high, as they have been for centuries in China after such disasters. The Chinese never could afford to build tremor-proof structures in their several earthquake zones. They needed a way to warn people in advance.

Li, along with other Chinese scientists, had been studying the old earthquake records from north China.He saw a pattern that fit his own theories of how the Chinese crust was splitting and buckling. Clarence R. Allen, a prominent Cal Tech geophysicist, has called the Chinese work in cataloging their records "a major . . . contribution to modern seismology . . . No other part of the world has a record this complete.

Allen said the Chinese appear to have reliable records back to 1484 of quakes as small as those comparable to a magnitude of five on the present Richter scale while records of similar reliability for southern California go back only to 1930.

Lie saw several signs of upcoming quake activity in Hopei, the province that surrounds Peking. He spent much of the last five years of his life hiking and taking notes in Hopei's mountains and rivers.

The Hsingtai quake and the surrounding geological structures convinced him that the tremors would be moving northeastward. In March 1967, an earthquake did hit Hochien county northeast of Hsingtai. In July 1976, five years after Li's death, the second most destructive quake in the world history hit Tangshan, northeast of Hochien on the same line from Hsingtai.

Backed by Li's interest in earthquake prediction and his personal prestige, Peking officials in the late 1960s organized the largest quake prediction team ever. Tens of thousand of peasants and workers learned to read instruments and record well-water level changes and unusual animal behavior. By 1975 they had forecast, through public announcements directing people out of their homes, at least a dozen quakes, some involving substantial savings in lives.

American scientists like Press, of MIT, who visited China in 1974, point out that Chinese officials do not have to justify themselves to the electorate when they issue a quake alarm that turns out false, as has happened. Yet there can be no doubt that China's program is significant and merits international "attention," Press said after his trip. "The Chinese have essentially doubled the earth's data base with respect to actual premonitory changes: in radon (a radioactive gas) and well-level measurements they have compiled more data than everyone else combined.

Repeating one of Li's favorite themes, the Chinese press in recent months have begun talking again about the time of Marco Polo. "Our science and culture flourished," said one Chinese reminiscence of their invention of paper, printing, gunpowder and rockets.

The ache of that old dream of changing the world through science, and the nightmare of the 1976 quake, seem to have galvanized the Chinese around the example of Li Szu-kuang. Armed with old records, inexhaustible manpower, and overwhelming pride, his students may again shake the world.