We note the author's intriguing statement at the outset when he said "that it took men thousands of years to learn how to make" a match.
Also, he further highlighted how problematic it was to depend on nature when he said "in the early history of the world, nature had to kindle all the fires, for man by his own effort was unable to produce a spark".
To express the problems further, the author also says that they would have to guard the fire but the fire would still go out sometimes and then they would have to go on long and difficult journeys