A strange explosion shattered a window in a ground floor room of Thayer Hall last night. No one was seriously injured.

Robert W. Dobbie '53 of Thayer 46 had just retired, and was still awake when the blast broke his window, covering him with glass. Dobbie was protected by the bodclothing, and sustained only a minor scratch on his arm, although some glass did hit his face.

So far, the police have no idea who set off the blast. Chief Alvin R. Randall of the University police is taking personal charge of the investigation.

"It's a good thing Dobbie wasn't standing near the window," he said. "The blast was strong enough to cause serious injury."

Possibility of Bomb

The object which caused the explosion had apparently been placed on the window sill, police said. Dobbie said he did not hear any noises outside the window prior to the explosion.

The only clues are a circle of tin, two inches in diameter, and a five-inch piece of iron pipe. Randall also gathered a small quantity of grey powder from the window sill. He is sending all the items to the Cambridge police for chemical analysis.

The explosion went off at 11:55 p.m. and was of such intensity that it shook the whole building. A large pall of smoke followed the blast.

Besides completely wrecking the first floor window, the explosion also broke a pane in the window of Thayer 52, directly above.

Pieces of glass and wood from the sill of the window of Thayer 46 littered the ground. The force of the explosion was enough to splinter the entire sill, also knocking out a piece of wood panelling inside the room.

Randall applied a match to part of the powder he found. The powder did not flare, so he said he thought it could be dynamite. Though still not sure what detonated the bomb, police believed the condition of the sill would indicate a fuse rather than a percussion cap.