Page:Popular Science Monthly Volume 45.djvu/490

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was, it is true, suspended for a time. A curious incident, bearing on the rapidity of construction, is related. A cooper, who could not obtain work at his own trade, applied for employment, and was put with the excavators in the shield. He was not accustomed to the use of the spade or shovel, the drawknife being his tool. It was hard work digging the tenacious clay with a spade, the only effective tool in its removal being a long, narrow spade, such as tile-ditchers use in England. The next day the cooper appeared with a drawknife of semicircular form, about six inches across, and, despite the jokes of his fellow-workmen, set to work with it. It was soon found that he could shave away the clay much more rapidly than it could be dug out. All the workmen were soon provided with drawknives, and it is probable that tool has come to stay as a means of tunneling in sticky clay.

The accompanying illustrations will give an idea of the character, progress, and appearance of the work after completion.


A STUPENDOUS scheme has recently been seriously suggested for the utilization in British waters of the energy of ocean currents for the purpose of distribution of power and light by means of electricity to centers of population at distances up to hundreds of miles from the source. This is nothing less than the proposition to dam the Irish Channel at the Mull of Cantire, where the distance between the Scotch and Irish shores is only fifteen miles, and where the energy of the current from the north is, so far as human requirements go, infinite—that is, would have to be expressed in scores of millions of horse power.

That this proposition is being regarded with some degree of seriousness may be gathered from the fact that a series of hydrographic surveys of the bottom of the channel has been made and charts prepared of the coasts and of the highlands on both sides from which materials might be conveniently got for building the dam. The report of an engineer detailed for the purpose is to the effect that there are no engineering difficulties in the way; by which is meant that, given the means to proceed, it is a possible thing to do, and is, compared, for instance, with the erection of the Brooklyn Bridge, a piece of work requiring merely enough brute force.

The idea is not primarily to afford a land junction for purposes of easier communication—although, of course, if the dam were constructed, a railway would be laid across—but, as mentioned, to give