example a layer of quartz wool 97 can be positioned at the bottom or distal end of the combustion tube to support a layer of furnace reagent 99 such as calcium oxide on kaolin for scrubbing out sulphur combustion products a second layer of quartz wool 101 can be positioned above the furnace reagent which in turn supports a layer of tungsten oxide 103 which is used to assure complete combustion of the sample to the desired constituent gases a third layer of quartz wool 105 is positioned on top of the tungsten oxide and supports a circular cup shaped ceramic crucible 107 in the combustion zone of the furnace since the inner combustion tube 77 is made of quartz the loading of the various layers of materials can be done outside of the furnace where the packing process can be observed by the technician this also provides consistency of operation for the furnace since the technician can observe each layer of material being put into the inner combustion tube and can determine the amount of packing pressure for example to be applied to each layer in an embodiment of the vertical combustion furnace the overall height of the furnace is approximately fifteen inches a cross section of the furnace would be a square approximately nine inches on.