sun, which remained shining brightly through a broad clear gap between two patches of cloud-strewn sky. On another occasion considerable preparations had been made for some photographic observations during an eclipse of the sun. The observatory stands on the eastern side of the valley of the Exe, which is flanked on its western side by a long ridge of hills going up to 800 feet above the sea. Beyond these hills lies the deep, narrow valley of the Teign, and beyond that the granite ramparts of Dartmoor, 1000 feet above the sea. The wind was blowing gently across the two valleys, and shortly before the eclipse began a broad strip of thin cloud formed above and rather towards the eastern side of the Exe valley, just where the sun was, while at the same time the sky was practically clear half a mile further east, and bright sunlight was streaming down on the ridge between the two rivers a few miles towards the west. The cloud was never thick enough to quite hide the sun, so that the eclipse was easy to watch with the naked eye; but in spite of fairly rapid movement of the cloud masses as they drifted before the sun, they kept on forming in just the same place, and completely prevented the carrying out of the programme planned. It is almost certain that the phenomenon was brought about by an upward moving wave marking the place where the level of approaching saturation was upheaved by the disturbance caused by crossing the two valleys and intervening ridge. These two instances are not quoted as examples of a rare occurrence, but as definite simple instances of a phenomenon which may be constantly observed, and as proof that the conformation of the ground does exercise an influence upon the distribution of cloud.