Abstract
In the exercise of my profession, particularly in reference to questions re­lating to harbours and tidal rivers, I have frequently had occasion for a train of observations on the rate of the rising and falling of the tides, continued through at least one whole series of them. Such observations have usually been made at intervals of fifteen minutes, and in order to exhibit the rates of rising and falling in the different periods of the same tide, and the differences of the several tides, I have represented them in the form of a chart. The Plate No. IV. exhibits one of those charts which was made previously to the commencement of a new entrance to the London Docks. The use of it was to ascertain for what length of time there would be a given depth of water about the said entrance, and in the channel of the river near to it, during the different tides.