In section 15 of daylight saving franklin uses the rhetorical device of repeating the sentence structure in i demand i expect i know in order
a. try to get an award or recognition for his clever thinking.
b. reinforce, in a clever way, his message of the benefits of using daylight instead of candlelight
c. to make his essay easier to read.
for the great benefit of this discovery, thus freely communicated and bestowed by me on the public, i demand neither place, pension, exclusive privilege, nor any other reward whatever. i expect only to have the honour of it. and yet i know there are little, envious minds, who will, as usual, deny me this and say, that my invention was known to the ancients, and perhaps they may bring passages out of the old books in proof of it. i will not dispute with these people, that the ancients knew not the sun would rise at certain hours; they possibly had, as we have, almanacs that predicted it; but it does not follow thence, that they knew he gave light as soon as he rose.