Among the works of Joseph Bertrand, his book entitled The Founders of Astronomy even gave me a definite date; and since I knew it had appeared in the course of 1865, I concluded that the fitting out of the Nautilus hadn't taken place before then.
Entre las obras que allí vi de Joseph Bertrand, la titulada Los fundadores de la Astronomía me dio incluso una fecha de referencia; como yo sabía que dicha obra databa de 1865, pude inferir que la instalación del Nautilus no se remontaba a una época anterior.