that each outer cavity opening is centered on a radial line extending from the longitudinal center axis of the housing through the center of an inner cavity opening to the outside wall 38 both the inner cavities 50 and outer cavities 54 are circumferentially sloped about their respective concentric circles such that the longitudinal axis of each is at an angle to and lies in a plane normal to an intersecting radial plane through the housing 34 each of the inner cavities 50 is however oriented at a greater slope then the outer cavities 54 the reason for the difference in slope between the outer cavities 54 and the inner cavities 50 will be discussed below the base 58 of the housing 34 is shaped to be accommodated within the piston 20 the lid 62 to the upper compartment 42 of the housing 34 has the timer 66 secured to its bottom surface by means of the screws 74 which extend through the top surface of the lid 62 the timer 66 is a spring driven mechanical type in the preferred embodiment the lid 62 is secured to the lower compartment 43 by means of the tang 70 shown in fig6 and 7 rotatably connected to and extending from the timer 66 engaging the upper lip 82 of the retainer 78 the upper lip 82 of the retainer 78 fits flush within the recess 84.