I am composed of copper, and I am heated by means of the same metal. I expand the cop

I am composed of copper, and I am heated by means of the same metal. I expand the copper, and cause it to form an excellent conductor of heat. I mark the progress of the heat, from the time it begins to act upon the copper, until it has produced a sufficient effect upon the metal to cause it to melt the wax, or to burn the wood. I also mark the progress of the heat from the time it begins to act upon the iron, until