S1: The advancement of science is not a secret or a mysterious process.
S6: What is he to think but to marvel at the skill of science, and to fear its power?
P: No one tells the layman about the years of experiment and failure.
Q: If it sometimes seems so, that is just because the day-to-day work of science is so unspectacular.
R: How is he to know what has not been done, or to guess the labour of what has?
S: You hear nothing from the research worker for years, and then, suddenly, there is the result in the headlines; penicillin or the jet engine or nuclear fusion.
The proper sequence should be: