The development of the Laussedat phototheodolite and its use at Brazil-Argentina boundary

Abstract

This paper discusses the historical role of the phototheodolite and its interchange between technique, its users and the results obtained. Thus we sought to: explore its technical and scientific background, highlighting the changes and continuities of different features of the instrument and its techniques, especially from the perspective of the history of science; analyze its arrival in Brazil through its use on the Brazil-Argentina border; investigate the construction and the musealization of the phototheodolite as scientific heritage present in the collection of the Museum of Astronomy and Related Sciences (MAST). Developed in France in the mid-nineteenth century, this instrument melded the geodetic technique of angular measurement of the theodolites with the newly developed technique of photography. In Brazil, two of these instruments were imported by the Republican government in the late nineteenth century to take part in the instrumental collection destined to the solution of Brazilian cartographic problems, such as the unresolved borderline issue with Argentina. The Commission for the Demarcation of Limits between Brazil and Argentina (1900-1905) chose this instrument because of the possibility of overcoming topographical obstacles, as in Iguaçu Falls, hardly solved with conventional methods; and by the presence of the astronomer Henrique Morize of the Astronomical Observatory, which mastered both the necessary handling techniques. Finally, after becoming obsolete due to technical innovation the phototheodolite was musealized by MAST in the exhibition “Photography: Science and Art” in 2012. This scientific instrument’s “biography”, from its construction to the current exhibition, allows a broader understanding of the history of Brazilian scientific heritage.

Keywords: Brazil-Argentina border, scientific instruments, Henrique Morize.