Locating cannons by sound ranging in World War I

In From the Other Side, April 2005, there is a discussion by Gerhard Koppner concerning Ludger Mintrop, events of World War I, and early developments of the seismic method. Mintrop, considered to be the father of the seismic refraction method, is given credit for locating cannons with his mechanical seismographs, but the Allied counter-battery forces had much more success. Mintrop was unable to convince the German Command to use his methods until late 1918, just before the war ended. French, British, and Canadian forces used sound ranging and flash spotting early in the war as described by Pierre Berton in his 1986 book, Vimy, and also described in various Web sites. Although sound ranging uses air, not the solid earth, the technology was comparable to modern earthquake source-location methods.