THE OCCURRENCE OF SPRINGS IN MECHANICAL SYSTEMS IS COMMON, AND SPRINGS OFTEN REMAIN AFTER A FIRE. WHEN A SPRING IS HEATED TO A HIGH TEMPERATURE AND THEN COOLED, CERTAIN PHYSICAL PROPERTIES OF THE SPRINGS CHANGE. AN EXPERIMENT WAS DESIGNED TO FIND OUT IF HEATING SPRINGS ABOVE THE EUTECTOID TEMPERATURE AND THEN COOLING WOULD CHANGE THE SPRING CONSTANT AND TO DETERMINE IF A RELATIONSHIP EXISTED BETWEEN A SPRING HEATED IN TENSION VERSUS ONE HEATED IN A RELAXED STATE. THE TESTING PROGRAM TO EVALUATE CHANGE IN THE SPRING CONSTANT CONSISTED OF OVER 80 SPRINGS HEATED FROM 1350 DEGREES F TO 2000 DEGREES F BY 50 DEGREE INCREMENTS. TEMPERATURE SPRING CONSTANT RELATIONSHIPS DID EXIST FOR THE SPRING SIZE TESTED. AS THE TEMPERATURE TO WHICH A SPRING WAS RAISED INCREASED AND THEN AIR-COOLED, THE SPRING CONSTANT DECREASED FROM ITS ORIGINAL VALUE. THIS RELATIONSHIP APPEARED TO HAVE NO TIME DEPENDENCE AS LONG AS THE SPRING BEING HEATED WAS UNLOADED. OVER 100 SPRINGS WERE TESTED IN THE TENSION VERSUS RELAXED STATE PART OF THE SPRING EXPERIMENT. AN INDICATED BY SLOPES OF NORMALIZED SPRING RATE VERSUS DEFLECTION CURVES, THERE WAS A TREND THAT THE SPRING RATE DECREASED WITH INCREASING PRELOAD. THIS WAS VERIFIED AT ALL TEMPERATURES EXCEPT 1600 DEGREES F AND 1800 DEGREES F. RESULTS OF THE OVERALL EXPERIMENT DEMONSTRATE THE POTENTIAL USE OF MECHANICAL PROPERTIES IN FIRE AND ARSON INVESTIGATIONS. REFERENCES, TABLES, AND FIGURES ARE INCLUDED, AS WELL AS SUPPORTING MATHEMATICAL EQUATIONS. (DEP)