What is is Elmo’s marginal product of labor after he hires a second worker?

How does thoreau defend his approach in the second paragraph of "economy" inwalden? -he uses the word "t" because he feels it sounds more interesting-he does not use first-person point of view because his is a fictional account-he uses first-person point of view to get his readers' attention-he uses the word "t" for the sake of sincerity and honesty.