73048276
Apr 2, 1975
May 24, 1977
HEATING EQUIPMENT-NAMELY, AN APPARATUS FOR HEATING ONE OR MORE ROOMS FROM A SINGLE FIREPLACE BY RECOVERY OF HEAT FROM THE CHIMNEY
Environmental Control ApparatusCONSTRUCTION MATERIAL-NAMELY, NATURAL AND ARTIFICIAL STONES, CEMENT, LIME, MORTAR, PLASTER AND GRAVEL; AND FIREPLACES
Nonmetallic Building Materials