The old battleship Revenge is continuing with experiments in the control of fire by aeroplanes. To date it is clear that was owing to the long range of fire, wireless is the only effective method of signalling from aircraft to the ship. Signals in the opposite direction were made at first by the ship’s searchlight. But this proved unsuitable as it was difficult to keep the searchlight accurately trained, and the task of reading its messages was difficult for the observer in the air. and requires good weather. These drawbacks, together with the need for good weather and a long-distance means of communication, led to the fitting of experimental receiving sets to a few seaplanes and aeroplanes. Tests have demonstrated that this system works and further experiments will continue to refine the process.