What are some early examples of large international scientific collaborations?

Question

The Large Hadron Collider (LHC) in CERN is well known for being one of the largest international collaborations to look for fundamental particles. Other big collaborations include the International Space Station, the Human Genome Project, the Manhattan Project, LIGO, etc.

Were there any pre-modern large international scientific collaborations? Some kind of quest for El Dorado or the philosopher's stone but in a collaborative way. If there is no such pre-modern collaboration and if most of the large collaborations were from the last century, which was the earliest?

I am looking for a collaboration, where many scientists (let's say more than 100) from different nationalities go to the same place to share research insight about a topic or build an experiment.

Answer 1

The conversion to the metric system in Continental Europe in the 1870s was a coordinated process, involving scientists and politicians from a multitude of nations. Apart from the processes in the various individual nations, the International Bureau of Weights and Measures was established in 1875. The initial period of the Bureau, with much laboratory work, later called the heroic years, culminated in 1889 with the completion of the prototype of the meter and the kilogram.

Answer 2

They didn't all go to the same place, but many, hundreds?, of scientists took part in expeditions all over the world to observe the 1761 and 1769 transits of Venus. Perhaps the most famous of these was the Banks/Cook voyage to the Pacific

"In 1761 numerous expeditions were made to various parts of the world so that precise observations of the transit could be made in order to make the calculations as described by Halley—an early example of international scientific collaboration. This collaboration was, however, underpinned by competition, the British, for example, being spurred to action only after they heard of French plans from Joseph-Nicolas Delisle. In an attempt to observe the first transit of the pair, astronomers from Britain (William Wales and Captain James Cook), Austria (Maximilian Hell) and France (Jean-Baptiste Chappe d'Auteroche and Guillaume Le Gentil) traveled to destinations around the world, including Siberia, Newfoundland and Madagascar... For the 1769 transit (taking place on 3–4 June N.S., 23 May O.S.), scientists traveled to Tahiti, Norway, and locations in North America including Canada, New England, and San José del Cabo (Baja California, then under Spanish control)."

Answer 3

Struve Geodetic Arc was a series of geodetic measurements conducted in (according to borders at that time) Russia, Sweden and Norway between 1816 and 1855.

The purpose was to more accurately determine the shape and size of the Earth. From the 2005 summary by J. R. Smith:

The work on the Russian part of the arc was carried out jointly by Imperial staff officers, the Dorpat Observatory and the Central Observatory of Poulkowa. That on the Scandinavian sector was carried out by Swedish and Norwegian experts, with the assistance of astronomers and equipment from Poulkowa Observatory.

Answer 4

Here are two older examples. The first is ancient Mouseion (Musaeum) founded c. 300 BC after the Alexandrian conquests that briefly unified the Hellenistic world, a prototype of modern academies. However it had broad scope not restricted to a specific research project. Its classical age ended with the expulsion of intellectuals from Alexandria in 145 BC by Ptolemy VIII:

"The Musaeum was an institution founded, according to Johannes Tzetzes, by Ptolemy I Soter (c. 367 BC – c. 283 BC) at Alexandria... Rather than simply a museum in the sense that has developed since the Renaissance, it was an institution that brought together some of the best scholars of the Hellenistic world, as Germain Bazin compared it, "analogous to the modern Institute for Advanced Study in Princeton or to the Collège de France in Paris."... More than 1,000 scholars lived in the Mouseion at a given time. Staff members and scholars were salaried by the Mouseion and paid no taxes."

The second is Maragheh observatory founded by al-Tusi in 1259, who justified the undertaking to Hulagu, Genghis Khan's grandchild, by the need to compile new astronomical tables adapted to Persian locations:

"Men of mathematics, science, and astronomy came to the Maragheh Observatory from across the Islamic world and further. According to historical texts recovered from the observatory, the site had a reputation so widespread it had reached as far as China... A number of other prominent astronomers worked with Tusi at the observatory, such as Muhyi al-Din al-Maghribi, Mu'ayyid al-Din al-'Urdi, from Damascus, Qutb al-Din al-Shirazi, and Hulagu's Chinese astronomer Fao Munji, whose Chinese astronomical experience brought improvements to the Ptolemaic system used by Tusi. After 12 years of intense work by Tusi and other scientists... the tables were compiled in the Zij-i Ilkhani."

The obsevatory lost its funding after 1282, and became inactive by c. 1300.

Answer 5

I would think that the so-called Magnetischer Verein, initiated and led by Gauß and Weber in Göttingen, qualifies. It formed a network of magnetic observatories that measured the elements of the geomagnetic field for several years in the 1830s according to a common protocol and involved participants especially from the German states, Austria, and Russia (including Finland, which was a part of the Russian empire at that time). The Verein also had its own report series.