THE CHILD'S CONCEPTION OF PHYSICAL CAUSALITY WAS INVESTIGATED. THREE METHODS OF INVESTIGATION WERE USED. THE FIRST METHOD WAS PURELY VERBAL, AND CONSISTED OF A SERIES OF QUESTIONS DIRECTED TO CHILDREN, REGARDING SOME NATURAL PHENOMENON. THE SECOND METHOD INVOLVED A HALF-VERBAL, HALF-PRACTICAL APPROACH, WHEREIN A SPECIFIC REFERENCE TO NATURAL PHENOMENA IS BROUGHT INTO THE QUESTIONING. THE THIRD APPROACH USED ELEMENTARY EXPERIMENTS THAT REQUIRED EARLIER ANSWERS TO BE EXAMINED AND APPLIED TO THE SPECIFIC SITUATION. THE CHILD'S RESPONSES WERE ANALYZED FOR VARIOUS STAGES OF DEVELOPMENT. SUCH ANALYSIS REVEALED CONSISTENCY THAT ALLOWS GENERALIZATIONS TO BE MADE AS TO THE NATURE OF THE CHILD'S CONCEPT OF PHYSICAL CAUSALITY AT VARIOUS AGE LEVELS AND AT VARIOUS STAGES OF DEVELOPMENT. IN SECTION I, EXPLANATION OF MOVEMENT, DISCUSSION FOCUSES ON (1) THE NATURE OF AIR, (2) THE ORIGIN OF WIND AND BREATH, (3) MOVEMENT OF CLOUDS AND HEAVENLY BODIES, AND (4) WATER CURRENTS AND MOVEMENT DUE TO WEIGHT AND FORCE. SECTION II, DEALING WITH PREDICTION AND EXPLANATION, CONSIDERS (1) THE FLOATING OF BOATS, (2) THE LEVEL OF WATER, AND (3) THE PROBLEM OF SHADOWS. SECTION III INVOLVES EXPLANATION OF MACHINES, AND DEALS WITH (1) MECHANISM OF BICYCLES, (2) THE STEAM ENGINE, AND (3) TRAINS, MOTOR-CARS, AND AIRPLANES. SECTION IV, THE CHILD'S CONCEPTION OF REALITY AND CAUSALITY, IS A SUMMARY AND CONCLUSION, AND DEALS IN DETAIL WITH THE IDEAS OF (1) THE CHILD'S REALITY, (2) CAUSALITY AND THE CHILD, (3) THE CHILD'S IDEA OF LAW, (4) ASSIMILATION AND IMITATION, (5) CHILD LOGIC, AND (6) LOGIC AND REALITY. THIS DOCUMENT IS AVAILABLE FOR $1.95 FROM LITTLEFIELD, ADAMS AND COMPANY, 81 ADAMS DRIVE, TOTOWA, NEW JERSEY 07512. (DH)