b'Book Reviewrecent developments of quantum gravity,are currently using these meters, asthe University of Sydney in 1893, pre-the existence of the Higgs boson, etc. none of the US companies were verydating the ones referred to in this book There are, of course, many seriousinterested. However, Australian andby nearly four decades.publications that cover the field of thisCanadian companies have recently beenChapter 9 also describes the book. The seminal paper in Geophysics,providing a service using these meters indevelopment of a revolutionary 70 (6), 2005, Historical developmentAustralia. electronic type of meter, which was of the gravity method in explorationIn the case of airborne gradiometry, thenamed CG-3 by Scintrex. Australians by Misac Nabighian and nine othersmost recent reference for the relevantwill know that the design of this meter formally reviews the history of thechapter is dated to the year 2000.was foreshadowed in the PhD thesis gravity method in the language ofHowever, there have been helicopterof Andrew Hugill (not Hurgill as geophysicists. That paper deals withand airship deployments since then.here). Andrew was awarded his PhD by all the main topics covered in MilsomsOther types of gradiometers that haveFlinders University in South Australia book, and more. However, it does onlybeen under development for over ain 1984 for his design of the Flinders deal with the subject up to 2005 anddecade are also not mentioned. Thesegravity meter. The Flinders meter was one might hope that a book publishedinclude the super-conducting typessucceeded by the CG-3, then the very in 2018 would cover subsequentsuch as those using vibrating strings orpopular CG-5, and, in 2016, the CG-6 progress. Unfortunately, apart from aniobium bars. (Andrew Hugill pers. comm. March, brief acknowledgement of the very latest2019).(2016) developments in gravity metersOf course, publishing constraints with micro-electromechanical (MEM)mean it can be difficult for any book toIn addition, when reading about types accelerometers, other earlier types ofinclude the latest information about aof gravity gradiometers in operation, modern meters in use since 2005, such asrapidly evolving field. In this context thesome Australians will be surprised to super-conducting quantum interferenceinclusion of details about commercialfind that the super-cooled meter built devices (SQUIDS), are not mentioned. matters that occurred decades ago canat the University of Western Australia seem irrelevant. This particularly appliesusing an innovative system involving Readers with a good knowledge ofto information supplied about thetwo crossed niobium strips kept at 4K the gravity method will also noticecompany Scintrex, where, Accountingis not mentioned.the absence of a few importantirregularities appeared, auditorsIn conclusion, this book is not a developments. For example, in Metersresigned and in May 2000, Rybak wascomprehensive coverage of the history at Sea, the placing of meters on theforced out. Why do we need to learnof gravity measurement. However, it sea floor is not mentioned. Suchabout Rybaks departure from Scintrexcould be a useful introduction to the deployments have been carried out bymore than 18 years after it occurred?subject for people with only a laymans Scintrex (a company whose businessMany new developments have takenknowledge of physics or geology affairs are described in detail in thisplace in Scintrex since 2000, but theand people who know little about book) since 2010. The use of boreholelatest discussed by Milsom is a referencethe Earths gravity field . Much of the gravity meters is another omission.to the CG-5 meter, which first becamecontent is related to Milsoms own Borehole gravity meters, which areavailable in 2002. working experience between the late necessarily small in order to fit into slim1960s to late 1970s. There is not a great boreholes, have been used in hard rockWell informed Australian geophysicists,deal of new material for experienced situations since 2008. and in particular readers of ASEGsgeophysicists well versed in the gravity Preview, will notice some shortcomingsmethod. However, as the publishers In Meters in the Air, the history of thein parts of this book of relevance to development of airborne non-gradientthem. For example, when readingclaim, such practitioners are likely to meters is described, including theabout the development of springtypeenjoy the history section.famous paper by Sigmund Hammer,meters in Chapter 9, The Rise and FallReviewed by Airborne gravity is here. This section endsof Springs, they will remember thatRoger Henderson with the remark that only the Russiansthe first meter of this type was built atrogah@tpg.com.auAUGUST 2019 PREVIEW 42'