How long does it take to set a fire with a magnifiing glass?

Answer 1

There are a couple ways to start a fire. One way is to use lighter fluid and a match. Another is to use lighter fluid and a lighter. Another is to get dry grass and two flint rocks, and spark the two rocks until fire is made. Another is to rub to certain kinds of sticks together on a rock in dried grass to start a fire. Another way is to put gunpowder on the ground around dried, or dead, grass, and strike the pile of gunpowder, which will cause a small explosion of sparks, which creates a fire in the dried or dead grass.

Answer 2

You can put dry grass under some twigs, catch those on fire by finding the parabola. Then all you have to do is build up from there.