Solve times for this jigsaw puzzleShare your solve times with your buddies
The first "friction match" was invented by English chemist John Walker in 1827. Early work had been done by Robert Boyle in the 1680s with phosphorus and sulfur, but his efforts had not produced useful results. Walker discovered a mixture of antimony sulfide, potassium chlorate, gum, and starch could be ignited by striking against any rough surface.
Share this Jigsaw Puzzle
Wed Leaning Tower of PisaTue Fern on BrickMon Chain TensionerSun Cactus PurpleSat Horse Jump OverFri Working HorsesThu Flowers in a WallMore Previous Puzzles