Discussing the difference between Western types of water-wheels and the Chinese types - where the Western types have vertical axles and Chinese horizontal ones - Needhamn has the following little interesting footnote:

"It will later be shown that this distinction runs through the whole of Chinese and Western ancient and medieval engineering. Chinese technicians always tended to mount wheels horizontally, and Western technicians vertically."

Quite possibly, I think, the explanation for this is that in the Western countries they borrowed the idea of a rotating device from the starry heaven as it looks far north, while the Chinese borrowed from the way the heavens looked close to the equator.

A look at the map reveals that China is located at about latitude 35^o N, whereas e.g. Holland is situated about latitude 55^o N. Due to the warming effects of the Golf Stream agriculture is possible farther to the north in Europe than on the east coast of the Pacific.

Easter Island is located at about 27^o S and therefore they ought to think of horizontal axles. And then - of course - Chinese ideas may have dominated all of the circum-Pacific area.