Air gets very hot when it is compressed under high pressure. A classic example would be the heat that is created when one uses a bicycle pump. But when the air is compressed in a firepiston it is done so quickly and efficiently that it can reach a temperature in excess of 800 degrees Fahrenheit. This is hot enough to ignite the tinder that is placed in the end of the piston which has been hollowed out to accept it. Ancient examples of the tube itself are of hardwood, bamboo, or even horn. It is closed on one end, very smooth inside and accurately bored. Equal care is taken in the creation of the associated piston. A "gasket" of wound thread, fiber, or sometimes leather insures a proper seal for successfully creating the compression. This gasket is "greased" to help with the seal and to allow free travel of the piston. The walls of the bore must be perfectly straight and polished smooth.