Emerson uses various rhetorical devices, such as the ones you have mentioned, making him sound much more conversational than cerebral and philosophical. He wants his ideas to be accessible to everyone—he isn't trying to write or speak to a learned audience only—since he's pushing for educational reform. He wants schools to do things differently than they have been doing, so he has to win people over. The effect of his use of many such devices is that he seems more congenial, more approachable, and even more reasonable and relatable, making his ideas about reform seem all the more friendly and reasonable too.
One example of Emerson's control of pacing comes early in the paragraph, as others have pointed out. The first two sentences, as you can see, are rather long and grammatically complete.
So to regard the young child, the young man, requires, no doubt, rare patience: a patience that nothing but faith in the medial forces of the soul can give. You see his sensualism; you see his want...
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