b'Book review MEASURING TERRESTRIAL MAGNETISM: the evolution of the AIRBORNE MAGNETOMETER and the first anti-submarine and aeromagnetic survey operations. People, Planes, Places and Events 1100s-1949.W.D. (Doug) Morrison. to WWII. Morrison documents the earlywhich ended up being relatively use of magnetic compasses in mining,successful. The magnetometers were also measurements of magnetic declinationinstalled in blimps, as well as a variety of and its importance in navigation, andfixed wing aircraft.the growing understanding that certain rock types are strongly magnetic and effect the earths magnetic field. In 1785, the first airborne magnetic measurements were observed in a manned balloon. In the mid-1800s, a number of country-wide ground magnetic surveys were carried out. The method became an accepted tool in exploration and mapping of buried iron ore deposits. During WWI, the first investigations into the practicality of using magnetics for the detection of submerged submarines took place. Magnetic measurements were made in aircraft and airships, including a flight by German Graf Zeppelin in 1930 for solely geological reasons. The saturated core fluxgate magnetometer was invented in Germany in 1928, but Published jointly by the Australianthe development was not published Society of Exploration Geophysicists anduntil 1936. Morrison also documents Geoscience Australia, 2020. extensive airborne magnetic surveysFigure 1 (Figure 39e).Victor Vacquier at Gulf carried out in the USSR in the late 1930sResearch and Development Company invented the Paperback AU$70.00 + postage (Australiaand during WWII, using induction coilairborne fluxgate magnetometer He died in 2009 at and International)technology, which had relatively lowthe age of 101. Obituary by Shor and Sclater (2010).sensitivity, 60-100 nT, but successfully ASEG Members Discount Pricediscovered a number of iron ore AU$45.00 + postage via secure Memberdeposits.loginPart 2 tells the story of US and British This book is a tour de force ofgovernment efforts to develop meticulous research combinedmagnetometers with the sensitivity and with detailed documentation ofpracticality to detect submerged enemy the development of instruments tosubmarines. Hare and Vacquier (Figure1) measure the earths magnetic fieldsubmitted a patent application for a spanning the last millennium. Thenew fluxgate magnetometer in 1940, author has a long career in the practicalbut to have this continuously measure application of airborne geophysicalthe earths changing magnetic fieldFigure 2 (Figure 48).The USAAF Sea-Searchmapping, together with enthusiasmwhilst mounted in an aircraft (Figure2)Attack and Development Unit (SADU) Douglas B-188 for geophysical history and the rareand at any latitude on earth was aBolo BuNo 07530. One of a series of photographs research skills and perseverance toproblem which occupied the defencetaken near British West Indies and Martinique pursue primary sources. His astonishingestablishments in the US and Britain for12 July 1942. These are the earliest identified attention to detail, combined withmuch of WWII. Compensation for thephotographs of an operational aircraft with a careful analysis of (sometimes)magnetometer or MAD mounted in a stinger. USAF. magnetic effects of the aircraft itselfPublic Domain. Various sources including NARA.conflicting descriptions of equipmentwas a major issue. Using source material and events, has produced a volumewhich was not released until after thePart 3 (almost half the book) describes unsurpassed as a history of thewar, Morrison carefully documents thethe largely post-war development of practical development of airborneequipment advances and test flightsimproved fluxgate magnetometers, magnetics. to develop a practical MAD (Magneticpaper chart recorders and ancillary The book is divided into three parts: Airborne Detection) system and theequipment for navigation and flight numerous missions carried out duringpath recovery, to the point where Part 1 covers historical magneticthe second half of the war usingsystems were practical for mineral measurements and magnetic surveys upprogressively upgraded equipment,and petroleum exploration. Much of 47 PREVIEW OCTOBER 2021'