No it isn't. He is trying to use one experiment to prove one point, but in a different scenario, he tries to use the opposite of what was previously said to make another point. Basically, what hes says is "The world cannot be round because of x. However, x-1 proves that the Earth is flat, but only the way I want it too, not if it works out for anybody who believes in a round Earth. I am right, and anybody who disagrees is wrong. Even if I really am wrong."
Apparently, the library where I live don't carry the other book in question, but the librarian said it sounded like a good title for a fiction work. So, I checked out the new Terry Pratchett instead, which by the way, is a fiction/fantasy book. I still can't believe some of you tried to use his work in some of your arguments. Pratchett, while an outstanding author, writes fiction, fantasy, satire, parodies, and spoofs. His work is a comedy, not a basis for an argument. It'd be like the world leaders watching "Saturday Night Live", and to make their decisions.
And for all of you writing me random insults and getting mad at me for "doubting your beliefs" or not taking part in your little conspiracy:
If you're going to run around with your underwear on your head proclaiming that you are king of the jellyfish, be prepared for others to have a laugh at your expense. Even if you are right. (Nobody believed Newton, Einstein, or any other philosophers or scientists for years after they had passed, and many who have been right were executed for holding a different views.) And at least if you took the jellyfish belief and ran with it, you might come up with some evidence that is less disputable or harder to disprove.
I came here open minded attempting to learn why you believe what you do, but it seems the best argument any of you have is in the form of an insult. If people do laugh at you, it's because you've given them nothing but ammo in their case. You are the kid the wet himself in front of the whole school back in high school (although, some of you are just reaching that stage, let me tell you there's a long road ahead of you), and all the jocks made you the new target because of easy it was to do so.
Oh, and having read most of your responses and arguments, I am sure that at least one of you has read "Earth Not a Globe", but I hope he talked real slow when he was explaining it to the rest of you. Judging by your replies and limited vocabulary (which seems to include nothing more than a few big words that you practiced and your choice profanity), I doubt more than half of you could read the first chapter by yourself.