Acknowledgements

Chapter 1. Introduction

1.1 Raison d’etre

1.2 A language for new sciences

1.3 Quantifying the evolution of ‘geophysics’

1.4 Geophysical journals

1.5 Bibliographical note

Chapter 2. Terrestrial magnetism I. Understanding the magnetic field – from mystification to quantification

2.1 Lodestones and the earliest magnetic compasses

2.2 The terrella

2.3 Gilbert’s treatise

2.4 Magnetic declination

2.5 Long-term changes in declination

2.6 Halley’s four-pole model

2.7 Daily changes in declination

2.8 Magnetic inclination

2.9 Magnetic intensity

2.10 A technological breakthrough

2.11 Coulomb’s torsion balance

2.12 Magnetic currents

2.13 Changes in magnetic force in time and space

2.14 Legendre, Gauss and the method of least squares

2.15 Gauss and geomagnetism

2.16 Final proof of the inverse-square law

Chapter 3. Terrestrial magnetism II. Into the field

3.1 Geomagnetic maps and the terrestrial magnetic field

3.2 Changes in the field with time

3.3 Rock magnetism

3.4 Mineral exploration

3.5 Return to the sea

Chapter 4. Applied electrical and electromagnetic methods

4.1 Natural earth-currents and self-potential

4.2 Artificial currents and the search for ore

4.3 Electro-magnetic prospecting begins

4.4 From radio to radar

4.5 From ore-bodies to salt domes

4.6 Minerals again

Chapter 5. Gravity surveying and the ‘Figure of the Earth’ from Newton to CHAMP

5.1 The length of a seconds pendulum

5.2 Arc lengths and ellipticity

5.3 Spheroid shape and pendulum measurements

5.4 The attraction of mountains

5.5 The torsion balance and other methods

5.6 Gravity corrections, regional gravity-mapping and the concept of isostasy

5.7 From the Eötvös torsion-balance to the gravimeter

5.8 Pendulums at sea

5.9 The arrival of the gravimeter

5.10 Vibrating strings

5.11 Free-falling corner-cubes

5.12 Superconduction

5.13 Borehole gravimetry

5.14 Airborne gravimetry

5.15 Gravity gradiometers

5.16 Into space

Chapter 6. Shaking the Earth: from volcanology to seismic surveys

6.1 Volcanoes

6.2 Earthquakes

6.3 Mapping the frequency of earthquake occurrence

6.4 Earthquake distribution in time

6.5 Instrumental detection of earthquakes

6.6 Earthquake magnitude

6.7 The modern era

6.8 Locating the origin of an earthquake

6.9 Understanding the deep Earth

6.10 The beginnings of seismic prospecting

Chapter 7. The heat of the Earth

7.1 Early history of heat-measuring instruments

7.2 Near-surface geothermal measurements

7.3 Temperatures in mines and deep boreholes

7.4 Heat-flow through the continents and the seafloor

7.5 How to explain the Earth’s heat?

Chapter 8. Aspects of geodynamics

8.1 From mechanics to the solid Earth

8.2 A layered Earth

8.3 The enigma of mountain chains

8.4 The viscosity of the Earth

8.5 Isostasy

8.6 Have the continents moved?

8.7 Convection within the Earth

8.8 Tides, tilts and strains

Chapter 9. Radioactivity

9.1 From waste-tip to colourant

9.2 Early sources of uranium

9.3 Early sources of thorium

9.4 Towards radioactivity

9.5 Early investigations: radioactivity in nature

9.6 Development of measuring instruments

9.7 The search for uranium

9.8 Nuclear well-logging

9.9 The source of the Earth’s heat

9.10 Geochronology

Subject index

Person index

Howarth provides a deep view of the history of those geophysical sciences of the 19th and 20th centuries bordering most closely on geology, a task for which he is well qualified. He studied geology in the 1960s, he taught the application of statistics to geology for thirty years, and he has published broadly on mathematical geology. In a series of journal articles he has also used this expertise to examine the often unexplained quantitative methods used to map Earth’s magnetic declination in the 18th century. He also applied his extensive background in graphical methods in the geosciences to the history of mineralogy and petrology. In short, Dr. Howarth is a geologist with historical sensibilities and an eye for the roles of mathematics and physics in geological development. This important book culminates decades of historical research.

Gregory A. Good (West Virginia University, U.S.A)

Excerpt from review originally published in the International Union of Geological Sciences journal Episodes, August 2025.

If ever examples are needed of how nurturing curiosity-driven science supports a seedbed of unforeseen applications that benefit humanity – then Richard Howarth’s memoir is the place to go. As noted in the introduction, The Emergence of Geophysics discusses “the development of geophysics, from its earliest days into the twentieth century”. These journeys explore a wealth of geophysical techniques from their infancy, including magnetism, gravity surveying, geo-electrics, seismology, heat-flow, geodynamics and radioactivity.  

Readers may be familiar with the use of magnetic lodestones as basic compasses a thousand years ago – but Howarth takes us all the way through the progress in instrumentation that led to marine magnetic surveys and the discovery of plate tectonics. The development of gravimeters takes a striking turn from early pendulums in the 1700s (including Nevil Maskelyne’s famous Schiehallion experiment in Scotland and Pierre Bouguer’s less-successful measurements on Ecuador’s Chimborazo Volcano), to twentieth century regional mapping that used spring-based instruments, as well as the use of satellite-tracking technology to map Earth’s gravity field. Some of the journeys are pretty wild – such as the historical use of earthquake damage to locate epicentres – but they have led to the development of the seismic reflection methods that have underpinned much of society’s wealth-creation attributable to our science. As expected from an author who spent much of his career in applied science, there are extensive examples of how these methods evolved through prospecting for Earth’s resources. Given this is a memoir that looks at the early foundations of geophysics and the scientific edifices built upon them, don’t expect to find discussions of modern subdisciplines such as geodesy, a field that has revolutionised our understanding of active tectonic processes. 

Yet, there is still so much more here. Howarth asks whether readers expect a history of geophysics to have been written by a geophysicist. Being a user of geophysical data, one step removed from its practice, has perhaps provided Howarth with perspective. It certainly helps him to place the history of physical phenomena research into broader context and attribute key technical and methodological developments that are widely used today. For Howarth, this research has clearly been a labour of love and is reflected in the memoir being an excellent, methodical and illuminating read – with fantastic use of historical images. The production values are a credit to the Geological Society of London’s Publishing House. It’s a must-read, not just for geophysicists but for all interested in the origins of our science. 

Reviewed by Rob Butler, Geoscientist, 04 June 2025.