Thomas Sopwith's Geological Teaching Models

These twelve wooden geological teaching models, made in 1841 by the 19th-century engineer and surveyor Thomas Sopwith, were designed to teach geology - the study of the Earth. The different types of wood represent different geological formations, highlighting the orientation of mineral veins and coal seams under the ground. The models are based on measurements of mining districts from the North of England.

Since ancient times, astronomers on the Korean peninsula have observed the night skies, painting star charts on the walls of tombs, erecting observatory towers, and recording celestial phenomena, such as comets and eclipses.

The Whipple Museum of the History of Science owns a unique artefact of 18th-century Korean court astronomy: a massive folding screen preserving the knowledge of both East Asian and Western astronomy. The screen displays three main visual representations of the heavens: a diagram of celestial bodies, including the sun, moon, and Five Planets, a pair of Jesuit planispheres, and a 14th-century Korean star chart of ancient Chinese origins.

The Jesuit planispheres and the diagram of celestial bodies were copied almost directly from star charts assembled in 1723 by the Jesuit astronomer, Ignatius Kögler, with the help of fellow Jesuit engraver, Fernando Bonaventura Moggi. The 14th-century Korean star chart is itself a reproduction of a significantly older star chart, which was allegedly gifted to the Korean court by a Chinese emperor.

The Whipple's Korean astronomical screen was assembled around 1757 during the Chosŏn Dynasty (1392-1897), the longest ruling dynasty in Korea. At least three other almost identical screens were produced around the same time, and although we are not certain which historical figures were involved in their direct production, it's likely the Korean Bureau of Astronomy produced the screens for the royal Chosŏn court.

As much of the screen displays star positions that were out-of-date by the time of its creation in the mid-18th century, the screen was probably not used for positional astronomy, but rather as a didactic device used in teaching or lecturing, or as a memorial to a Sino-Korean astronomical heritage.

Folding screens are a prominent feature in the history of East Asian art. They were a popular furniture object for the wealthy élite to display in their homes and doubled as a movable room divider. Though most screens displayed decorative paintings, some became vehicles for cartographic display.

Almost everything on the Korean astronomical screen was copied from other sources, with just slight tweaks and revisions. The historical value of the object lies in the choices made by the compilers: what originals were worth juxtaposing with one another on this elaborate screen? What did they think was worth changing or leaving untouched?

Itinerant astronomers

During the 17th and 18th centuries, Korean astronomers took many trips back and forth between the Chinese imperial metropole of Beijing and their own home base in Seoul, the capital of the Korean kingdom during the Chosŏn Dynasty. Through these frequent travels, Korean astronomers learned mathematically-based astronomical methods and techniques taught by the Jesuit astronomers living in Beijing. They then brought many books and instruments with them back to Seoul.

The 14th-century Korean planisphere displayed on the Whipple's screen is an anomaly of 18th-century East-Asian astronomy. At a time when most Chinese astronomers were trying to learn "New Methods" from the distant West, the Korean screen uniquely honours the astronomical knowledge of ancient China by including a planisphere, or star map, that reproduced star positions from around the 1st century CE.

Tracing back to the ancients

According to the inscription on the Whipple's screen, the original of this Korean planisphere was lost in a river near Pyŏngyang in 672 CE during the invasion of the ancient kingdom of Koguryŏ. This original had supposedly been a gift from an unspecified Chinese emperor to an ancient king of Korea. A rubbing of this original stele was recovered, and in 1395, King T'aejo, founder of the Chosŏn Dynasty, ordered a new stele to be made from the rubbing.

Remnants of antiquity

Though the inscription that accompanies the 1395 stele claims that the court astronomers revised the star map to reflect 14th-century star positions seen from Korea, the 1395 version still displays star positions from the 1st century CE. The only change was that the Korean astronomers moved the innermost ring on the star map, denoting the circle of perpetual visibility, to reflect the latitude of Seoul. The circle of perpetual visibility demarcated all the stars that could always be seen from a particular position on Earth. The outermost ring, the circle of perpetual invisibility, as well as the celestial equator and ecliptic circles still reflect 35 degrees latitude, the coordinate of the ancient Chinese capital.

Sopwith's models

The son of a builder and cabinet maker, Thomas Sopwith (1803-1879) started work as an apprentice to his father. After completing his apprenticeship he changed career and became a surveyor. He drew geological cross-sections of Alston mines in 1828. His 1834 book A treatise on isometrical drawing provided a means of visualising geological and mining plans in three dimensions and was well received. It is with his background of cabinet-making and interest in geology that Sopwith fashioned his models.

The models are made to a very high standard. Constructed from 579 separate pieces of wood, they were laminated and joined together; the surfaces were then carved by hand. The models were available in sets of six or twelve, and in various sizes. Another set is held at the Sedgwick Museum of Earth Sciences.

Models and books

This set of twelve models was sold in a shop run by James Tennant - mineralogist to Queen Victoria. The shop was situated three doors down from the Geological Society of London at Somerset House and was frequented by many of the important geologists of the time. By 1844 Gideon Mantell commented that "it had become too well known to require comment".(1)

Sets of six or twelve models came in a case, whose binding was designed to resemble a large book. Inside the case a small publication by Sopwith, Description of a Series of Geological Models was included to accompany the models.

The relationship here between teaching models and books is worth stressing. In his book, which describes models that teach geological principles, Sopwith uses books themselves as a means of modelling a geological feature (Image 2).(2) Models and book, are then all housed in a case that is bound specifically to resemble a large volume to sit on a shelf. The models also feature in Lyell's 1841 Elements of Geology(Image 3).(3)