This is a Walker Commodore Electric Log, which was a device used in hydrographic surveys of the sea floor. Manufacted by Thomas Walker & Son Ltd of Birmingham, England, the device has a main dial that is calibrated 1-100 miles and two subsidiary dials measuring 1-10 and 100-1000 miles respectively. The log also has a screw-on glazed port and two brass impellors, all contained within a fitted pine case.
