From a stylistic standpoint, no, "on" and "in" are not interchangeable. It was an oversight on my part that I used "on" the first time and "in" the second time in this sentence in my posting above:
For starters, read my essay "The grammar of numbers and time" that's posted on the Forum, then follow it up with "The genesis of the numbers 1 to 9," also posted in the Forum.
Since I'm using American English, I should have consistently used "on" in both instances. It must be kept in mind, though, that this is just a matter of convention and preference. My understanding is that it’s the other way around in British English: “Londoners live
in a street and stay
in farm cottages
at weekends,” but “New Yorkers and English-speaking Manilans live
on a street and stay
in farm cottages
on weekends.”
You may want review some of the other usage differences between American English and British English by clicking this link to
“How American English and British English Differ,” an essay of mine that I have posted on the Forum.
For preposition usage in American English, I suggest you check out
“Lesson #8 – Specific Rules for Preposition Usage” in the Forum by clicking the indicated link.