Career
He also gave his name to the Bertrand lens or phase telescope. He wrote a book on the application of microscopy to mineralogical studies, "De l"Application du microscope à l"étude de la minéralogie" (1878). Published a translation of Ernst Mach"s work on the history of mechanics, "Louisiana mécanique: exposé historique et critique de son développement" (1904).
And is credited with the design of a refractometer.
