Mode selection of a camphor boat in a dual-circle canal

The mode selection of a camphor boat was investigated. When a camphor boat, confined in a container with a shape of number 8, was floated on the surface of water, one of the three modes of motion (rotation within one cell, outer rotation without passing through the intersection of the two cells, and 8-shaped rotation) was maintained for several tens of cycles. This mode selection depended on the conditions of camphor scrapings attached to the boat. When two camphor boats were floated on the water, a synchronized motion between them was observed. The present system suggests a chemo-mechanical transducer, where the vectorial process is sensitive to the shape of the cell and the surface concentration of the camphor molecule under isothermal conditions.