Meridiana: The Adventures of Three Englishmen and Three Russians

This novel can be found under alternate titles such as "Adventures in the Land of the Behemoth", "Measuring a Meridian", and "Meridiana" or "Adventures in South Africa". Three Russian and three English scientists depart to South Africa to measure the 24th meridian east. As their mission is proceeding, the Crimean War breaks out, and the members of the expedition find themselves citizens of enemy countries.