472 THE POPULAR SCIENCE MONTHLY. 



was, it is true, suspended for a time. A curious incident, bearing 

 on tlie 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 accus- 

 tomed 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 char- 

 acter, progress, and appearance of the work after completion. 



A PROPOSITION FOR AN ARTIFICIAL ISTHMUS. 



By ERNEST A. LE SUEUR. 



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 hydro- 

 graphic 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 con- 

 structed, a railway would be laid across but, as mentioned, to give 



