There are a lot of embarrassed trend watchers around the country. The new mood on campus took a sharp turn toward familiar action this week, as startled observers who had counted out student militance saw buildings occupied, classes picketed and police forces of varying strengths shooing away antiwar demonstrators.

The latest Nixon escalation of the war in Indochina brought an immediate, though somewhat diffused, response from students at Harvard: Thursday night's strike meeting tried to pull together threads of protest after Tuesday's lightning attack on the CFIA. In the midst of planning antiwar actions, the Emergency Action Coalition found itself with a new issue Wednesday when President Bok announced Harvard's decision not to sell its 671,876 shares of Gulf Oil stock.

Silkscreen posters advertising the strike meeting curiously, though according to some antiwar planners inexplicably, began to focus on action against two wars--one in Vietnam, one in Angola where Gulf has substantial investments. And when dawn broke Thursday, two dozen black students from Afro and the Pan African Liberation Committee took the initiative, seizing Massachusetts Hall. There they remain, in what is by far the longest building occupation in Harvard's activist era. University Hall, brutally cleared by waves of police after students had held the building for hardly 15 hours in 1969, provides little comparison for the Mass Hall protesters who enter their third full day of occupation this morning.

Nor was the Mass Hall break-in as unexpected as University Hall. For almost two months, Afro and PALC leaders had contained their frustration with the Administration's refusal to meet their divestiture demands. The idea of a building occupation had been considered on several occasions; the first mill-in in University Hall on February 24 very nearly became a takeover. In a meeting there, demonstrators voted not to hold the building, and since then similar votes or caucuses had decided to put off any occupation until Harvard made a decision on divestiture.

When PALC leaders were handed that decision Wednesday afternoon, few doubted that a closed Afro meeting Wednesday night would first reject Bok's explanation to retain the stock, and then ponder a response. It was largely a matter of which building would be taken, when and how. But it was no surprise: two Harvard policemen don't ordinarily spend nights in Massachusetts Hall. As Bok said of the previously delayed, now real, occupation. "We weren't exactly unaware of the possibility."