"The calorific value of air-dried (15% m.c. wet basis) leucaena wood is about 3,900 kcal/kg (4,640 kcal/kg oven dried), similar to that of other non-resinous hardwoods."
"The bed of the riffle, however, is constructed of some porous material, such as leather, non-resinous wood, or cement, which serves as the diaphragm upon which the mercury rests, and separates the fluid metal from the electrolyte beneath."
"Second, carve a flat fireboard of soft, non-resinous wood that is about the same thickness as your drill's diameter."