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THE NATIONAL GEOGRAPHIC MAGAZINE 



THOUSANDS AND THOUSANDS OF FISH 



WERE KILLED BY THE EXPLOSIONS 



OF THE MINES 



The sub-chasers kept the larger ships con- 

 stantly supplied with cod, pollack, and herring, 

 which are most abundant in the North Sea. 

 Occasionally a curious specimen, such as shown 

 above, was picked up by a vessel. 



the sweepers only knew that they had 

 been selected to sweep the hitherto invin- 

 cible barrage. The ships had suddenly 

 been ordered to the navy yards at Boston 

 and Norfolk, where curious appliances of 

 every description had been placed on 

 board. Workmen invaded the ships and 

 began stringing wires and installing elab- 

 orate electrical panels. Some one said 

 these were to keep the mines from ex- 

 ploding when their vessels struck them. 



Then, too, rumors had reached home that 

 the Patuxent had narrowly escaped de- 

 struction while experimenting in the bar- 

 rage. 



The day following the arrival of the 

 sweepers Rear-Admiral Strauss returned 

 to Inverness and hoisted his flag on the 

 Black Hawk, the flag and repair ship of 

 the force. 



Not a moment was to be lost. If 

 humanly possible, the barrage must be 

 cleared away during the year, and that 

 meant by October, for from then on the 

 short days and severe storms would make 

 our efforts futile. 



As soon as the necessary overhaul inci- 

 dent to a transatlantic voyage had been 

 completed, the mine force got under way ; 

 the sweepers and six chasers headed for 

 the barrage ; the Black Hazvk and other 

 chasers for their new base at Kirkwall. 



THE RESULTS OF THE FIRST TRIP 



No attempt was to be made on this 

 first operation to clear a definite area of 

 mines. The object was experimental. 

 Several appliances remained to be tested, 

 chiefly an amplification of the Electrical 

 Protective Device whereby the mines 

 would all be exploded by an electrical 

 connection to the sweep-wire ; also, we 

 must know more definitely the present 

 condition of the field — what percentage 

 of the mines remained, and were they 

 still in the positions in which originally 

 planted, or had the storms and currents 

 scattered them about. 



At the end of two days the ships re- 

 turned to port, having accounted for 221 

 mines — less than half of 1 per cent of 

 the total number we had laid. The elec- 

 trical scheme for exploding the mines 

 was not • successful, and, even worse, it 

 had a most alarming effect on the mag- 

 netic compasses. The powerful solenoids 

 caused by the current in the insulated 

 sweep-wire wound around the drums had 

 made the compasses point as much as 

 ninety degrees from the magnetic me- 

 ridian ; and the navigators found their 

 ships actually going east or west when 

 they were thought to be headed north. 



The mines, as far as could be told. 

 were still in place and had not dragged 

 from their original positions. 



