OUR CHILDREN'S HERITAGE.

SIMILARITY. Macmillan Co. Made by Davidson Films. 1 reel, si., color, Super 8 mm. (Macmillan school mathematics program) Loop film. © Macmillan Co.; 31Dec69; MP21023.

SIMONE MARTINI (Filmstrip) Herbert E. Budek. 15 fr., color, 35 mm. © Herbert E. Budek; 1Dec65; JP12704.

SIMPLE MACHINES. See

MACMILLAN ELEMENTARY SCIENCE FILMSTRIPS.

SIMPLE TECHNIQUES IN SHAPING GLASS. Centron Educational Films. 9 min., sd., color, 16 mm. © Centron Corp., Inc.; 1May70; MP20635.

SINGER EDUCATION & TRAINING PRODUCTS. See

THIS IS THE SOVIET UNION.

SINO-ATRIAL BLOCK IN THE FROG HEART. See

PROPERTIES OF CARDIAC MUSCLE.