Introduction to the 1860 Solar Eclipse Documents

A few years ago I was reading through the catalogue of Airy Papers held at the Cambridge University Library and a set of 7 bundles of documents caught my attention. Unlike other volumes in the section about solar eclipses, this set of 7 volumes related to a single solar eclipse. Even their titles were similar as variations of the sentence: “The first part of a series on the expedition on board HMS 'Himalaya' to observe the total solar eclipse in Spain on 18 July 1860”.

[Woodcut depicting selected members of the Himalaya expedition - based on a photograph of one of the observing stations]

The next time I visited the archives I ordered the first volume of the series to see the types of documents it included. To my surprise, it included letters between Airy, the Admiralty, and many of the observers attending the expedition. These were letters that discussed preparatory measures, instruments, personal arrangements, and matters relating to the publishing the observations after the eclipse. The number of folios in the volume came to a total of 426. After taking a second look at the index of the volume, I noticed that the file was marked “A to D”. If this was only the part one of a grand total of seven, then were possibly around 2800 folios preserved in these volumes. For someone interested in the interactions between astronomers, this was a treasure trove of files. At the same time, I realised that going through the entire set in detail was a monumental undertaking. Since I didn’t have the time for such a project, I decided to put it aside as an idea at a later time.

[Illustrations accompanying the observations of the Eclipse by Henry S. Ellis]

In the following years, I applied for research grants/fellowships to undertake such a project, but I was unable to secure any funding besides offers for travel grants to visit the archives again. The distance between me and the possibility of the project grew further and further day by day. Then, in January 2020, I was offered a position with the possibility to relocate to Cambridge. This meant a proximity to the Archives, which raised my hopes for the project again. Then the pandemic hit. It was not until the summer of 2021 that I was able to take a look at the documents again. With access to the archives becoming easier again, I thought it might be time to explore the archival materials in more detail. The series of posts that I am commencing today will accompany my exploration of the archival materials.

[Colour chart accompanying the observations of the Eclipse made by Francis Galton]

The 1860 Solar Eclipse is best known for Warren De La Rue’s photographs taken of the celestial phenomenon. Historians have written about the eclipse in the past. Peter Hingley focused on De La Rue’s involvement and on his photographs of the eclipse. Holly Rothermel wrote in more detail about how De La Rue and George Airy viewed astrophotography at the time, and what role the 1860 Eclipse played in the development of the field. De La Rue was also the focus of David Le Conte’s article on the involvement of Guernseymen in astronomy. The all-encompassing history of solar eclipses by Littmann, Espenak, and Willcox briefly touched upon the 1860 expedition as a cooperative attempt by De La Rue and the Italian astronomer, Angelo Secchi, to take photographs of the eclipse from two different locations. Alex Soojung-Kim Pang wrote two articles [1] [2] and a book about Solar Eclipse expeditions as social gatherings, which included his findings on the 1860 expedition too. Manuel Canseco Caballe published a book that described in detail the various expeditions and parties that observed the eclipse. The information-rich book offers both lists, transcriptions, and summaries of the preparations, observations, and aftermath of the expeditions. Diaz focused on the involvement of Spanish men of science (especially Jose Monserrat) and their attempts to take photographs of the eclipse. Vitor Bonifacio presented about the involvement of Portuguese astronomers in the eclipse observations. The 1860 Eclipse was also observed in North America. J. E. Kennedy wrote three articles delving deeper into the American and Canadian expeditions. The surviving drawings and photographs also gained scientific interest in 1974, when J. A. Eddy compared more recent observations of coronal transients seen during the eclipse with drawings made during the 1860 eclipse.

[Layout of the HMS Himalaya showing the arrangement of the cabins on board]

Through these examples we see that the solar eclipse of 1860 has garnered frequent attention by historians. However, none of the accounts have presented a systematic description of the materials available for researchers at the Cambridge University Library. Therefore, the aim of this series of posts will be to provide a detailed overview of the surviving documents and to offer selected transcripts from the letters. By doing so, the posts will retell the history of the expedition from Airy’s point of view, who was preoccupied with organising the expedition for a party of astronomers travelling to Spain on board of the HMS Himalaya. As another outcome of the project, a detailed list of the individual items found among the sets will be made available.

[Photograph of the Eclipse taken at Labrador in 1860]

Rather than retelling the story in a chronological order, the posts will explore the documents in the same order as they were catalogued. The first three volumes of documents relate to the organisation of the expedition, which was organised alphabetically by the name of the correspondent. The second half of the set includes the accounts of the Eclipse that were submitted to Airy by the observers. These are similarly organised in alphabetical order. The purpose of this approach is two-fold. First, it demonstrates the difficulty in bringing together a coherent story of the expedition based on the current organisation of the papers. Creating an itemised catalogue of the individual items, will allow for modifying their order and showcasing how their reorganisation can highlight the key (and sometimes hidden) individuals in the organisation of the expedition. Second, the approach will allow readers to join in on the exploration of the archival materials as they are present in the archives. It allows the reader to follow along the letters as they are being explored, as opposed to being a passive participant of an overarching story. It opens up the possibility for the reader to suggest what documents I should transcribe in the future or what documents I should spend more time focusing on in subsequent posts. This way the reader can become a co-producer of the research project.

[A page from the special issue of the Memoirs of the Royal Astronomical Society (vol. XLI, 1879) relating to solar eclipses]

The written accounts of the astronomers found among archives were never published in their full extent. Instead, Airy wanted to publish the results of the observations in comparison to other eclipse observations taken during the nineteenth century. Since his duties as Astronomer Royal prevented him to collate such a publication, he asked Arthur Cowper Ranyard to carry out the work. (It is currently unknown why Ranyard was chosen, but I’m hoping to find more information about this as I am exploring the archives.) Ranyard’s work resulted in a more than 800 pages long special issue for the Memoirs of the Royal Astronomical Society. The publication included eighteen plates and numerous reproductions of drawings and photographs alongside the texts. The inclusion of accounts of the 1860 eclipse within such a publication shows that the Himalaya expedition was not seen as an isolated event. Instead, it formed part of a chain of expeditions throughout the nineteenth century, which were based on pre-determined research questions. By revisiting the papers relating to the organisation of the Himalaya expedition, the posts will hope to demonstrate who were the key players in determining the aims of the expeditions, how such aims were integrated into the research programmes, and what aims were deemed unsuitable.

The posts are currently scheduled to be published every Friday and you can subscribe to receive them via email here:

[Cartoon by Augustus De Morgan depicting the Eclipse expedition]