Despite serious losses by one assistant professor, most of the valuable books and documents stored in an Economics Department building that burned down Monday have been saved, department officials said yesterday.

"We were very lucky," said one of the building's former occupants after searching through the boxes of charred books and papers that demolition crews have taken to a basement at 1750 Cambridge Street.

Wrecking crews worked through yesterday to remove the rest of the salvageable material from the rubble at 42 Quincy Street.

Subramanian Swamy, assistant professor of Economics, suffered the heaviest losses. Swamy said that many irreplaceable notes from his research in Japan and Hong Kong have apparently been destroyed. They were lying on top of his desk, and Swamy said he has little hope of finding them.

A Cambridge firemen tried to save some of Swamy's handwritten notes by rushing into the burning building and throwing them out the window. But they are still lost in the snow, and Swamy said the ink has probably been washed away.

Thomas D. Willett, instructor in Economics, said he lost about $300 worth of books in the fire. However, Willett said he was "very fortunate" because he has found all the important research notes for his study of the U.S. balance of payments.

One Economics professor said "about as much damage was caused by water as by the fire itself." Five staff members who used the building said that their books were still wet, and one said he would have to "wait until the books defrost" to tell how many are still usable.

Monday's sub-zero temperatures may have saved many of the books from further water damage. A department teaching fellow said that the water froze as soon as it hit the furniture, forming a protective veneer over many desks and bookcases.

The ice also created bizarre scenes in the building's ruins Wednesday, as workers found desks encased in solid blocks of ice. One instructor said he spent the afternoon in the basement repository chipping away at pieces of ice to find his books and cards