While the main body of the book was about postures and movements of the body and energy, which Mr. Wu had no trouble interpreting, the introduction was basically a treatise about metaphysics.
It clearly took more than one man to move the cannons, which not only put a large number of men out of action, but meant changing positions as needed was an ordeal that might get them killed.
Moreover, even though humans have been upright for millions of years, our feet and back continue to struggle with bipedal posture and cannot easily withstand repeated strain imposed by oversize limbs.
If the dog's hackles are up, gives a low decibel growl, or engages in a predatory, stalking posture, then there is probably a danger in the environment.
For some unaccountable reason, as Arthur Dimmesdale felt the child's eyes upon himself, his hand - with that gesture so habitual as to have become involuntary - stole over his heart.