In 1781 an eminent French engineer proposed that, instead of one continuous breakwater, a number of large masses or congregations of stones, separated from each other on the surfaces but touching at the bases, should be built on the sea bottom, believing that they would break the force of the waves almost equally well. As a part of his plan he suggested that they should be sunk in large conical _caissons_ of wood, 150 feet in diameter at the base and sixty feet broad at the top. These wooden cones were practically to bind and keep the stones together. They were to be floated to the site with a number of empty casks attached as floats, then detached, filled with stones, and sunk. An experiment at Havre having been considered satisfactory, the Government accepted the idea, and ordered that operations should be immediately commenced at Cherbourg. A permanent council was appointed, as were officers and engineers. In 1783 barracks and a navy-yard were built, and at Becquet, a short distance from Cherbourg, an artificial harbour, capable of holding eighty small vessels for the transport of the stone, was literally dug out. On June 6th, 1784, the first cone was floated to its destination, and a month later a second was similarly conveyed, in the presence of 10,000 spectators. Before the latter could be filled with stones a storm, which lasted five days, half demolished it. In the course of the summer and autumn not less than 65,000 tons of stone were deposited in and around the cones. In 1785 several more cones were completed and sunk; at the end of the year the quantity of stone deposited amounted to a quarter of a million tons, and at the end of 1787 a million tons. At the end of 1790, when the works had been seven years in progress and the Government was getting very tired of the whole matter, between five and six million tons of stone had been dropped into the sea. M. de Cessart, the engineer, found that, in order to sink five cones per annum, he had to employ 250 carpenters, 30 blacksmiths, 200 stone-hewers, and 200 masons. One could hardly expect much permanency from a wooden covering sunk into the sea, and it is not surprising that, one by one, they burst, few lasting more than a year. The outbreak of the Revolution put an end, for some time, to the operations at Cherbourg.