Note 11 — MOUNTAIN OBSERVATORIES.

We are told that three American observers in the Rocky Mountains, belonging to the Eclipse Expedition of 1878, easily saw Jupiter’s satellites night after night with the naked eye. That their discernment is possible, even under comparatively disadvantageous circumstances is rendered certain by the well-authenticated instance (related by Humboldt, “Cosmos,” vol. iii. p. 66, Otte’s trans.) of a tailor named Schön, who died at Breslau in 1837. This man habitually perceived the first and third, but never could see the second or fourth Jovian moons.