The document discusses improving the efficiency of coal boilers through experimentation. It describes the current coal burning process and notes the efficiency ranges from 60-85%. The author then designs a experiment using a 3 factor design of experiments (DOE) to test the effects of oxygen percentage, coal bed depth, and stoker speed on efficiency. The results of the DOE show oxygen percentage and coal bed depth as the most significant factors. The maximum predicted efficiency of 80.71% is achieved with high oxygen percentage and deep coal bed depth. The author recommends these optimal settings to the Chief Engineer.