THE NATIONAL GEOGRAPHIC MAGAZINE 



87 



HOW A MINK IS ANCHORED AT THE DESIRED DEPTH BELOW THE SURFACE OE THE SEA 



The progress of a mine after it is thrown overboard is shown in Figures I to 6. When 

 a mine is dropped overboard, the mine proper (A) floats, while the box-like anchor (B) 

 slowly sinks. Inside the anchor is the mooring wire (F), which unwinds from a reel as the 

 anchor sinks. The reel is unlatched (E) by the downward pull of a plummet (C) at the end 

 of a cord (D), which is made the same length as it is desired to have the mine stay below 

 the surface. The plummet, being nearly solid metal, sinks faster than the more bulky anchor 

 box (see Fig. 3), thus keeping the cord (D) taut. As soon as the plummet strikes bottom, how- 

 ever, the cord slackens and the reel in the anchor box is locked, thus preventing any more 

 mooring wire from unwinding. The anchor continues to sink, pulling the mine case under 

 the water until the anchor strikes bottom, as in Fig. 6 (see text, page 91). 



possibilities, especially against subma- 

 rines.* 



* After putting it through some tests, the 

 Naval Bureau of Ordnance felt confident 

 that here was what they were looking for. 

 It was not long before the British naval 

 authorities came to think so too, and a 

 joint operation was projected, to be un- 



* The inventor to whom the author refers was 

 Mr. Ralph C. Browne, of Salem, Mass., whose 

 design for a submarine gun was adjudged im- 

 practical. One of the elements of this gun, 

 however, was recognized by Commander S. P. 

 Fullinwider, U. S. N., and his assistant, Lieu- 

 tenant Commander T. S. Wilkinson, Jr., U. 

 S. N.. in the Bureau of Naval Ordnance, as 

 having great possibilities if adapted to a mine 

 against submarines. Mr. Browne gladly ac- 

 ceded to the Naval Ordnance Bureau's request 

 to collaborate with its experts in the develop- 

 ment of such a mine. 



dertaken by the mining squadrons of the 

 two navies. 



The plan was to plant a mine field across 

 the North Sea, from Scotland to Nor- 

 way, a distance of 230 miles, or as far as 

 from Boston to New York. It was a 

 bold scheme ; some said foolish, impossi- 

 ble. Nothing like it had ever been un- 

 dertaken. Moreover, for lack of time. 

 tens of millions would have to be spent 

 outright, by the British as well as our- 

 selves, before a single mine could be 

 tested complete — most unusual proced- 

 ure, requiring great administrative cour- 

 age on the part of Rear Admiral Ralph 

 Earle, Chief of the Naval Bureau of 

 Ordnance, upon whom the odium would 

 have fallen had the mine proved a fail- 

 ure. But it was the onlv way to make an 



