Members of the radical November Action Coalition (NAC) clashed early yesterday morning with several hundred riot-equipped police in the narrow street outside M. I. T.'s Instrumentation Laboratory, but there was only one arrest.

The 375 chanting demonstrators set up an obstructive picket line outside the five entrances to 1-Lab 5 and its parking lot gates shortly after 7 a. m. Pickets marched in pairs, arms linked, in a rapidly moving circle outside each entrance.

Police-750 were on call, with between 200 and 300 actually participating in the dispersal-began marching toward the picketers at 9 a. m. equipped with clubs, rifles, tear gas, and dogs. All demonstrators were out of the area within half an hour.

No Serious Injuries

Fifteen demonstrators were reported injured, none seriously.

Yesterday's protest was part of a five-day action against war-related research planned by the NAC, a coalition of about 25 Boston-area radical groups. Plans for today include a mass rally at noon with M. I. T.'s Science Action Coordinating Committee (SACC) at Kresge Plaza.

Yesterday's action began at 6:10 a. m. in the M. I. T. Student Center when the tactics committee announced its decision to definitely center on 1-Lab no. 5-at 15 Osborn St.-where the principal research on the MIRV missile system is conducted.

Affinity Group

The demonstrators were divided into three aflinity groups. The largest-including M. I. T.'s Rosa Luxemburg SDS and the 32 Weathermen-were to picket the main entrance, and two smaller groups to block the parking lot gates.

The 70-member Harvard-Radcliffe contingent guarded the Osborn St. parking lot gate.

Marching in cadres out of the student center at 6:50 a. m. and through a heavy rain to the lab two blocks away, the demonstrators chanted "Ho Ho Ho Chi Minh" and "Power to the people," and carried NLF flags.

On the roof of the Instrumentation Lab at least eight policemen and plainclothesmen were stationed with radios. One police officer carried a rifle with a telescopic sight.

Immediately pickets formed at each of the entrances, moving swiftly with arms linked. Inside the building, about ten people-the I-Labs are open 24 hours a day an shifts change at 8 a. m.-could be seen in the doorway watching picketers through metal mesh window guards.

Three research workers in the I-Labs attempted to break through the picket lines individually around 7:45 a. m. but were jostled and shoved back by the demonstrators. One had to be pulled back by a friend and retreated across Albany St. to stand with other employees waiting for police to clear the pickets.

At about 8 a. m. an M. I. T. graduate student-who identified himself as Richard Kline, a member of Young Americans for Freedom (YAF)-suddenly began pushing his way through the picket line, fighting with the demonstrators. He did not break through the line.

Kline told reporters that he was trying to get into the lab to get some data, but later called the attempted entry "my own personal test" of the NAC's "obstructive picket."

At 8:20 a. m. Captain Joseph E. Cusack of the Cambridge Police Dept. read a declaration ordering everyone to clear the area or be subject to a heavy fine or arrest, and affirming his power to ask anyone for assistance in making arrests.