With reference to the "earth-shine" on the moon when in the crescent phase, Humboldt says, "Lambert made the remarkable observation (14th of February, 1774) of a change of the ash-coloured moonlight into an olive-green colour, bordering upon yellow. The moon, which then stood vertically over the Atlantic Ocean, received upon its night side the green terrestrial light, which is reflected towards her when the sky is clear by the forest districts of South America."[92] Arago said, "Il n'est donc pas impossible, malgré tout ce qu'un pareil résultat exciterait de surprise au premier coup d'œil qu'un jour les météorologistes aillent puiser dans l'aspect de la Lune des notions précieuses sur _l'etat moyen_ de diaphanité de l'atmosphère terrestre, dans les hemisphères qui successivement concurrent à la production de la lumière cendrée."[93] The "earth-shine" on the new moon was successfully photographed in February, 1895, by Prof. Barnard at the Lick Observatory, with a 6-inch Willard portrait lens. He says-- "The earth-lit globe stands out beautifully round, encircled by the slender crescent. All the 'seas' are conspicuously visible, as are also the other prominent features, especially the region about _Tycho_. _Aristarchus_ and _Copernicus_ appear as bright specks, and the light streams from _Tycho_ are very distinct."[94] Kepler found that the moon completely disappeared during the total eclipse of December 9, 1601, and Hevelius observed the same phenomenon during the eclipse of April 25, 1642, when "not a vestige of the moon could be seen."[95] In the total lunar eclipse of June 10, 1816, the moon during totality was not visible in London, even with a telescope![95] The lunar mountains are _relatively_ much higher than those on the earth. Beer and Mädler found the following heights: Dörfel, 23,174 feet; Newton, 22,141; Casatus, 21,102; Curtius, 20,632; Callippus, 18,946; and Tycho, 18,748 feet.[96] Taking the earth's diameter at 7912 miles, the moon's diameter, 2163 miles, and the height of Mount Everest as 29,000 feet, I find that Everest 1 Dörfel 1 ---------------- = ----, and --------------- = --- Earth's diameter 1440 moon's diameter 492 From which it follows that the lunar mountains are _proportionately_ about three times higher than those on the earth. According to an hypothesis recently advanced by Dr. See, all the satellites of the solar system, including our moon, were "captured" by their primaries. He thinks, therefore, that the "moon came to earth from heavenly space."[97] CHAPTER VI Mars Mars was called by the ancients "the vanishing star," owing to the long periods during which it is practically invisible from the earth.[98] It was also called πυροεις and Hercules.