During the expedition, King Mongkut and Prince Chulalongkorn were infected with malaria. The king died six weeks later in the capital, and was succeeded by his son, who survived malaria.
It has been argued that the assimilation of Western geography and astronomy into 19th-century Siam "proved that Siam equaled the West in terms of knowledge, and therefore the imperialists' claim that Siam was uncivilized and had to be colonized was unreasonable." This suggests that the Western form of these sciences may have saved Siam from actually being colonized by Western powers.