On Friday October 25th 1734, between three and four at night, an earthquake hit Sussex County in the South of England. Several days later, a local Duke named Charles Lennox wrote a letter to the Royal Society of London in which he reported on the various observations of the earthquake he had collected. The Royal Society was always interested in reports on remarkable natural phenomena and, like many other earthquake accounts, Charles’ letter was published in their journal Philosophical Transactions.[1] The letter included observations from a wide range of people. Charles was not present in Sussex to feel the earthquake himself, but related the experiences of his friends, his servants, and various citizens of the city of Chichester and surrounding places, such as shopkeepers, glovers, an innkeeper, a linen draper and his wife, a widow and her three daughters, a customs officer and several other ‘persons of veracity’. Early earthquake science was heavily dependent upon such accounts provided by lay observers, but their observations tended to be heavily abridged in the Philosophical Transactions. Indeed, the printed report mentioned that it was ‘unnecessary to trouble the Reader with each Certificate’ and merely provided a summary of the findings and the observers’ names. However, copies of many of these ‘certificates’ which Charles Lennox made his observers sign were kept in Letter Books in the Royal Society Archives in London.[2] Together with Charles’ letter itself, these testimonies offer a fascinating glimpse of daily life disturbed by a shocking natural event and recounted through the lens of scientific observation.
Early modern observations of earthquakes are interesting because there was little agreement about what was actually being observed. Theories on the causes of earthquakes ranged from underground explosions to electricity and lightning via sensory illusions produced by shockwaves in the air. Naturalists turned to lay observations in hope of finding evidence that might support or discredit one or several theories. The inclusion of eye-witness observations radically transformed the study of earthquakes. Soon, naturalists would not only debate about the cause of earthquakes, but also use comparisons of different accounts to find patterns in the extent and intensity of earthquakes. Although they had a very different theoretical conception of earthquakes, this methodological innovation of eighteenth century naturalists laid the foundations for nineteenth century seismology, which was heavily observer-based.[3] The inclusion of eyewitnesses is also interesting as an early form of ‘citizen science’. It was impossible (not to mention highly undesirable) to recreate an earthquake in an experimental setting, and so natural philosophers relied on those who had first-hand experience with the phenomenon. For most natural philosophical projects, such forms of lay participation remained confined to upper- and middle class gentlemen.[4] Yet the unpredictability and elusive nature of earthquakes meant that naturalists were keen to get their hands on whatever observations they could acquire, even if they sometimes remained prejudiced against those who provided them.
One of the observers of the 1734 earthquake was Martha Freeland, servant to a Chichester tallow chandler named Thomas Baker. She testified that:
‘she being abed between three and four o’clock in the morning, Oct: 25: 1734 did hear a chest of drawers hit and strike hard against the wall (to which they stood near) in her bedchamber, and then also she heard the drops (or hasps) strike, and rattle against the drawer and did also perceive her bed to rock (as it were easily) from feet to head of the bed. The drops also continuing to rattle, she did put by her curtain, to see if any body were in the room; but it being very dark she could discern nothing.’
Martha’s account is illustrative of three elements I would like to briefly explore. The first is the issue of authorship. The account was clearly not written by Martha Freeland herself, but by Charles Lennox. Yet it is not difficult to picture Martha Freeland giving additional details about the proximity of the drawers to the wall, the noise they made, and the ease with which her bed was rocking in order to convey a sense of the experience. There are also traces of later editorial changes: the reference to ‘the drops (or hasps)’ of the chest of drawers appears in exactly the same phrasing in several other testimonies, such as those of the linen drapers Andrew and Sara Adaire and that of one Mrs. Fletcher. Perhaps this small addition was intended to convey a sense of diligent scrutiny.
Secondly, Martha clearly ascribed the motion of her furniture to a different cause at first: she got up to see if there was not someone in the room with her. Similarly, one Richard Silverlock went to check under his bed to see if someone was playing a prank on him by lifting it up and the alderman John Lang ordered his servant to look whether his dog had gotten under the bed. In fact, only few observers initially associated the shakes with an earthquake, while most reached this conclusion after conversing with others and discarding alternative causes. Three sisters named Jane, Eleanor, and Sarah Tutte recalled discussing what they had just witnessed. Eleanor thought someone was trying to break into their room, while Jane ‘began to think of a ship being blown up; because she remember’d that of the Edgar Man of War’ [The HMS Edgar, which sank in Hampshire in 1711]. Only Sarah ‘immediately thought of an earthquake, to her very great surprise’. Elsewhere Matthew Fathers, a shopkeeper, fell into a great sweat because he reckoned something heavy had fallen over in his shop. Others noted that the shaking of their beds was too intense to be caused by the wind, which was not very strong. All these references indicate that it was difficult for lay persons to recognize and describe an earthquake. Though not unheard of, strong earthquakes were not very common in England. At first glance the inclusion of such doubts might make the accounts seem less convincing. On the other hand, it was clear that the conclusion of an earthquake was only drawn after carefully considering and discarding other, initially more likely hypotheses.
Finally I want to draw attention to how Martha described the motion of her bed. It was well known to naturalists that earthquakes were sooner felt by those who were not in motion. Because this earthquake hit at such an early hour, most observers were in an ideal position to sense the shocks. Charles Lennox had received a letter from a friend in Havant, a medical doctor named Edward Bayley, describing the same earthquake. In this letter, Bayley describes how he and ‘a learned and ingenious gentleman in this town’ both observed the earthquake from their beds. Yet whereas Bayley reckoned his bed to have moved from side to side, this gentleman observed being tossed from head to toe. The discrepancy was of course explained by the different positions of their beds: Bayley’s was positioned North to South whereas the other was placed East-West. Because a bed was situated in a known and fixed position in a room, it proved a strangely ideal site for observing the direction of the shakes. This is why Charles Lennox, in his brief discussion of the direction of the earthquake stated: ‘what Dr. Bayley of Havant says of the different Motions of the Beds, according to the different Situations they were in, is very well worth observing’. None of the other certificates collected by Charles mentioned the direction of the shakes. This might indicate that he collected them before receiving the letter and that Martha’s observation was rather unique in its detail with regards to this particular.
So how were these observations used to produce knowledge on earthquakes? First of all, naturalists were keen to gather many different ‘particulars’ in order to find out which phenomena accompanied an earthquake. One such particular that reoccurs throughout these observations is the absence of any strong winds. Because there was no clear consensus on the cause of earthquakes, such observations were key to distinguish the essential qualities of an earthquake from accidentals. More observations meant more unique particulars to consider. As we have seen, paired with a lack of experience this lack of knowledge also meant that earthquakes were difficult to recognize. Multiple accounts were therefore necessary to make sure that the phenomenon was indeed an actual earthquake. For Charles Lennox, ‘what confirms me in my opinion that there really was an Earthquake, is, that every body almost join in the same Description, as to the Sensation, the Hour of its happening, and the perfect Calm that was at that Time.’ Both these logics of collection implied that there was a limit to the amount of useful observations: either when no more unique particulars came in, or when it was clear that the shakes were felt universally. Charles wrote that he could have gotten ‘above fifty more accounts’, but that since ‘they all tend to the same Purport, I thought what I had already collected sufficient’.
Next to this very seventeenth-century approach to empiricism, with its emphasis on particulars and individual accounts, there are also signs of a new development in scientific observation. In the eighteenth century, naturalists collected observations not only to find interesting particulars or verify reports, but also to compare and synthesize accounts on a much larger scale.[5] Charles Lennox received reports from a variety of different places in Sussex and synthesized this information in a Précis, a small textual summary of the available data:
‘I observe the Shock was vastly more felt towards the seaside, as at Shoreham, Tarring, Goreing, Arundel and Havant. At my House of Goodwood, which is three Miles North of Chichester, and seven from the sea, it was not so perceivable as at Chichester and still less so than by the Seaside. I don’t hear as yet that it was at all felt in any parts of the vale on the north side of the Downs’.
Although Charles did not do so himself, we can place these points of data on a map. Doing so quite clearly shows a west to east pattern in the places where the earthquake was observed. The small differences in the way the earthquake was described also pointed Charles Lennox to the places where the earthquake was felt stronger. Using discrepancies between observations in this way, rather than discarding them, would prove essential for the development of seismology in later decades. The Royal Society meanwhile played its part to facilitate these kinds of comparisons. Under Lennox’s report, they printed another account ‘from the registers’ of an earthquake observed in Northamptonshire, noting that: ‘this Shock was perceived to extend more from East to West than from North to South; which Particular was likewise observed in the last Shock felt in Sussex 1734.’
The certificates signed by the observers of the 1734 shocks tell us much about the process of making of natural philosophical knowledge on earthquakes in the age before seismology became an established science. Yet they also offer a small peek into the lives of the many contributors to this enterprise. I would like to end this post with another certificate that shows the sometimes markedly different interests of observers and naturalists:
“Sarah, the wife of John Bryers of the City of Chichester, glover, saith, that on the 25th day of October 1734, she being abed with her husband between three and four o’clock in the morning, a little bell hanging in her chamber did make a little noise (or gingling), which she thought was occasion’d by somebody’s pulling the string in another chamber. But she going presently thither to the bedside (where her daughter Sarah lay with a child two years old) she found her daughter fast asleep. And saying ‘Sal, Sal’, she did not answer, until she stroak’d her face: and then she said: ‘did your ring the bell?’ And Sal said: ‘No.’”
[1] Lennox, Phil. Trans. Vol. 39, No. 444, pp. 361-367.
[2] Royal Society Archives, Letter Book Original, Volume 21, no. 43, Copy letter from His Grace Charles Duke of Richmond to Hans Sloane 31 October 1734 (LBO/21/43).
[3] See: Deborah Coen: The Earthquake Observers. From Lisbon to Richter (University of Chicago Press, 2013).
[4] See for instance Jan Golinski, British Weather and the Climate of the Enlightenment (University of Chicago Press, 2010) and Barbara Shapiro ‘Testimony in seventeenth-century English natural philosophy: legal origins and early development’, in: Studies in History and Philosophy of Science, 33, 243-263 (2002).
[5] Lorraine Daston, ‘The Empire of Observation, 1600 –1800’; J. Andrew Mendelsohn, ‘The World on a Page: Making a General Observation in the Eighteenth Century’, both in: Histories of Scientific Observation (Eds. Lorraine Daston & Elizabeth Lunbeck, University of Chicago Press, 2011).