"It's easy to fly like an eagle when you live among the turkeys."
From The Earth Review, 1895
(You can do this with your telescope. Just go to the beach, look at a ship and wait until it is out of sight. Then look through your telescope. You'll see the whole ship but this would be impossible if the earth was a sphere because we all know, a telescope can't see through a hill of water!)
“ A good many years ago a pilot in the Mauitius reported that he had seen a vessel which turned out to be two hundred miles off. The incident caused a good deal o f discussion in nautical circles at the time, and strange to say a seemingly well authenticated case of the same kind occurred afterwards at Aden. A pilot there announced that he had seen from the heights the Bombay steamer then nearly due. He stated precisely the direction in which he saw her, and added that her head was not then turned towards the port. . . Two days afterwards the missing steamer entered the port, and it was found on enquiries that at the time mentioned by the pilot she was exactly in the direction and position indicated by him, but about two hundred miles away.”— Chamber's Journal, Feb. 1895, p. 32. In the case o f both these ships the curvature would be 26,666 feet, leaving the vessels, after making a liberal allowance for the elevation of the observer, nearly five miles below the line of sight.— (Ed. E. R.,)
i spent over 15 years in different country's observing different phenomena and easely afterwards concluded that;
At the beach sitting on a high mountain i've never seen the sea bending at the sides at any radius point.
I walked over 10.000 km and never ever i felt like descending or ascending on a road while walking up to 70 km straight concerning an earth curve with the magnitude they present in text books....or cycling 10 hours nonstop.....
Because while walking you'll sometimes entre a vally in the lower portion of a mountain and climbing to 4000 km hight doesn't indicate, that the entire earths surface is bending at a constant rate (corner angle) or (anglular speed towards 360 degrees). You just descend little or ascend little. Our ascending and descending ability variates between few hundred m downwards and few thousand m upwards.
Just take your own steps and walk 1000 meter, look back and think back. "how did i walk, in a curve or just straight"