Then why has no one told the art schools that they're wrong?
Art schools are not necessarily interested in accuracy.
TB the book is all opinion after chapter 2 not fact :/ but when you believe something strongly you see what you want to see
Rowbotham presents two kinds of evidence in Earth Not a Globe. He presents
experimental evidence and he presents
empirical evidence. His water-convexity tests are experimental in nature while the rest of his work beyond Chapter 2 is empirical in nature.
For example; Rowbotham notes that deep coal mines tend to get hotter with depth. The deepest mines in Britain have steam pouring out of them constantly; as it gets hot enough for the air to condense. It is not possible to go into the mines without heavy protective gear and masks.
From this Rowbotham concludes, empirically, that the earth gets hotter with depth, as the weight of the earth causes compression and heat. Rowbotham further concludes that at some deeper depth the compression must be so great that rock liquefies; into a substance akin to the fiery magma which has been seen to erupt from volcanoes. Hence, the earth must be riding atop a great ocean of liquid magma, and there must be great quantities of liquid rock beneath us; an unprecedented notion for Rowbotham's time.