tar appears on the horizon, "the Sun should therefore look much larger" – if the Earth were a plane! Therefore, he argues, "the path followed cannot have been the straight course," – but a curved one. Now, since it is nothing but common scientific trickery to bring forward, as an objection to stand in the way of a plane Earth, the non-appearance of a thing which has never been known to appear at all, it follows that, unless that which appears to be trickery were an accident, it was the only course open to the objector – to trick. (Mr. Proctor, in a letter to the "English Mechanic" for Oct. 20,1871, boasts of having turned a recent convert to the Zetetic Philosophy by telling him that his arguments were all very good, but that "it seems as though [Mark the language!] the sun ought to look nine times larger in summer." And Mr. Proctor conclude's thus: "He saw, indeed, that, in his faith in "Parallax," he had "written himself down an ass.") Well, then: trickery or no trickery on the part of the objector, the objection is a counterfeit – a fraud – no valid objection at all; and it follows that the system which does not purge itself of these things is a rotten system, and the system which advocates, with Mr. Proctor at their head, a weapon to use – the Zetetic philosophy of "Parallax" – is destined to live! This is a proof that the Earth is not a globe.

Aristotle (who made quite a lot of observations about the spherical nature of the Earth) noticed that during lunar eclipses (when the Earth’s orbit places it directly between the Sun and the Moon, creating a shadow in the process), the shadow on the Moon’s surface is round. This shadow is the planet's, and it’s a great clue about the spherical shape of the Earth.
78) From Anchorage, Alaska at an elevation of 102 feet, on clear days Mount Foraker can be seen with the naked eye 120 miles away. If Earth were a ball 25,000 miles in circumference, Mount Foraker’s 17,400 summit should be leaning back away from the observer covered by 7,719 feet of curved Earth. In reality, however, the entire mountain can be quite easily seen standing straight from base to summit.