The periodic variations of the temperature of water have been studied for some months at the Scottish Marine Station at Granton. The only tidal basin which has been considered as yet is the haven formed by the irruption of the sea into Granton Quarry. It has an area of about 7 acres; the tidal entrance is on the west side, and is so situated that no water can enter until about half tide; then it comes in as a very rapid stream for about three-quarters of an hour, when the rate falls off, and near high water it is the same as that of the rising tide on the shore. The ebb is gradual until the tide has narrowed the channel by uncovering the sandbanks which lie on each side of the entrance, then it is rapid for about an hour and a half, after which the water runs out ext'remely slowly, and does not absolutely cease until the tide begins to re-enter; but for from four to five hours the water-level inside is practically unaltered. The depth of the quarry at low water varies from 5 to 8 fathoms in the parts where observations were made, and at high water the depth is slightly more than 1 fathom greater. The bottom shelves off abruptly from the bar at the entrance.