ScientificAmerican1915-03-13.jpg Scientific American 1913-07-12ThumbnailsScientific American 1915-03-20Scientific American 1913-07-12ThumbnailsScientific American 1915-03-20Scientific American 1913-07-12ThumbnailsScientific American 1915-03-20Scientific American 1913-07-12ThumbnailsScientific American 1915-03-20Scientific American 1913-07-12ThumbnailsScientific American 1915-03-20
The large transit circle at the Paris Observatory, now used only for obtaining accurate time.