How were fires lit before? From other fires, of course, to begin with. Two further techniques evolved around the world—the first generated heat by rubbing hard wood rapidly against soft, the second created sparks by striking hard stones against stone or metal. In both cases the heat or spark had to be "caught" by a flammable material nearby. Tinder could be most anything organic, but certain dried mushrooms were particularly valued. The ingenuity in the construction of bows for rubbing wood sticks, or the compact steel-silex-tinder kits of 17th-century soldiers is remarkable.
In the 17th and 18th century, as optics evolved, the convex burning glass became an important fire source, albeit a fair-weather one. Sparks also came from the newly discovered electricity. Still another source was invented in 1770 and has a fascinating connection to chemistry and physics. This is the pneumatic lighter, in which the heat generated in a rapidly compressed gas is sufficient to inflame tinder.