Counting apparatus

779,955. Counting-apparatus. DISTILLERS CO., Ltd. May 8, 1956 [Feb. 10, 1955], No. 3967/55. Class 106 (1). Apparatus, particularly for counting bacterial colonies, comprises a plate constrained to move in a direction perpendicular to its own plane relative to a base plate and urged in one direction against a stop, a micro-switch actuated by movement of the plate in the other direction and an electrical counter connected to the switch. Several arrangements are described. In one, Fig. 4, the plate is supported by a double parallelogram linkage and urged upwardly by a weight 14. In another, Fig. 6, a similar linkage is used and a cross-member 8 thereof is formed with an extension 10 on which acts a spring 21 adjustable by a screw 12. The extension 10 operates the microswitch 9. The stop is formed by a screw 16 projecting into a recess 17 in the plate 1. The base plate 3 is part of a box enclosing the linkage and containing a lamp arranged beneath the plate, which in this case is translucent. The lamp is switched off each time the microswitch is operated. In other arrangements, the plate is at an angle, which may be a right-angle, to the base, which in the latter case may be secured to a wall. In use, a dish containing the bacterial colonies is placed on the plate and the colonies are marked with a pencil, the counter being operated as each is marked. The plate may be arranged as the platform of a microscope.