1. IN A STORAGE BIN PROVIDED WITH MEANS FOR PERIODICALLY REMOVING AND INTRODUCING MATERIAL WHEREBY THE LEVEL OF MATERIAL WITHIN SAID BIN IS CONSTANTLY CHANGING, THE IMPROVEMENT COMPRISING LEVEL DETECTOR MEANS CONNECTED TO THE TOP OF SAID BIN, SAID DETECTOR MEANS INCLUDING A HOUSING, A TAPE REEL LOCATED WITHIN SAID HOUSING, A MOTOR FOR DRIVING SAID REEL AND A TAPE ADAPTED TO BE PLAYED OUT FROM OR WOUND ONTO SAID REEL DEPENDING ON THE DIRECTION OF OPERATION OF SAID MOTOR, A WEIGHT SECURED TO THE END OF SAID TAPE, MEANS FOR ACTUATING SAID MOTOR WHEREBY SAID TAPE CAN BE PLAYED OUT AND SAID WEIGHT LOWERED INTO SAID BIN, A WHEEL DISPOSED ADJACENT SAID REEL WITHIN SAID HOUSING AND ADAPTED TO BE ROTATED BY SAID TAPE, MEANS ASSOCIATED WITH SAID WHEEL FOR RECORDING THE EXTENT OF MOVEMENT OF SAID WEIGHT AND BEING ADAPTED TO RETAIN A READING CORRESPONDING TO SAID MOVEMENT WHEN SAID WEIGHT STRIKES THE MATERIAL WITHIN SAID BIN, MEANS FOR REVERSING SAID MOTOR WHEN SAID WEIGHT STRIKES THE MATERIAL STORED IN SAID BIN WHEREBY SAID TAPE IS ADAPTED TO BE WOUND ONTO SAID REEL, SAID HOUSING BEING PROVIDED WITH AN ELONGATED CYLINDRICAL MEANS HAVING ONE END SECURED TO THE HOUSING WITH THE OTHER END EXTENDING TOWARD SAID BIN, AN AXIS OF SAID CYLINDRICAL MEANS BEING DISPOSED GENERALLY IN THE SAME PLANE AS SAID TAPE REEL, SAID CYLINDRICAL MEANS COMPRISING FIRST AND SECOND CYLINDERS WITH SAID SECOND CYLINDER BEING SLIDABLY RECEIVED WITHIN SAID FIRST CYLINDER, SPRING MEANS HAVING ONE END FASTENED INTERMEDIATE THE ENDS OF SAID FIRST CYLINDER AND THE OTHER END ATTACHED TO SAID SECOND CYLINDER, SAID SECOND CYLINDER NORMALLY PROJECTING SUBSTANTIALLY BEYOND THE END OF SAID FIRST CYLINDER THROUGH THE ACTION OF SAID SPRING MEANS AND BEING ADAPTED TO BE FORCED INTO SAID FIRST CYLINDER IN OPPOSITION TO SAID SPRING MEANS, SAID WEIGHT HAVING A DIAMETER GREATER THAN THE DIAMETER OF SAID SECOND CYLINDER WHEREBY SAID WEIGHT WILL BE FORCED AGAINST SAID SECOND CYLINDER AS SAID TAPE IS WOUND ONTO SAID REEL.