Drawing on archival material in Utrecht and Rotterdam, we examine the geophysical surveys of Indonesia and Brazil carried out by Elie van Rijckevorsel during the period 1870 to 1890. We pay special attention to the complex interactions among university academics, government administrators and ministers of state, and private, ‘gentlemanly’ specialists. Making an appearance, in addition to Van Rijckevorsel, are the Utrecht polymath Christophorus Hendricus Diedericus Buys Ballot , the colonial and metropolitan astronomer Jean Abraham Chrétien Oudemans , colonial geophysicist Pieter (...) Adriaan Bergsma , French-Brazilian astronomer Emmanuel Liais , Colonial Minister Isaac Dignus Fransen van de Putte , and others. The decision of Van Rijckevorsel, an independently wealthy man of learning, to carry out a magnetic survey of the Malay archipelago spurred colonial authorities at The Hague to endow the finest geomagnetic observatory in the tropics. Van Rijckevorsel's interactions with academia and government suggest the extent to which wealthy Dutch patricians readily accepted government patronage for their scientific undertakings. A late-nineteenth-century Dutch ‘gentleman of science’ is seen to differ rather widely from his English counterpart of an earlier generation. An appendix reproduces, in English translation, correspondence from the early 1870s. (shrink)