laboratory instruments and apparatus, namely stirred reactors and control instruments therefor; non-stirred pressure vessels; acid digestion bombs in the nature of vessels for dissolving or digesting analytical samples in strong acids or alkalis under heat and pressure; microwave acid digestion bombs in the nature of vessels for dissolving or digesting analytical samples in strong acids or alkalis under heat and pressure using microwave energy for heating; cell disruption bombs in the nature of pressure vessels for preparing homogenates of cells and tissues, and for releasing components from plant and animal tissues, by rapid decompression with nitrogen; sample preparation bombs in the nature of vessels for preparing solid or liquid analytical samples for chemical analysis by digestion with strong acids or alkalis, or by combustion with oxygen in sealed pressure vessels; sulfur analyzers in the nature of units for determining sulfur in coal, oil or any oxygen-combustible material following sample preparation in an oxygen combustion bomb; proximate analyzers in the nature of units for collecting and storing analytical data for coal samples from other instrumentation, and for computing and reporting the moisture, volatile matter, fixed carbon and ash of said samples; balance interfaces in the nature of units for collecting, identifying and storing sample weights for analytical tests, and for transferring said data to other instrumentation upon request; communications network unit for fuel testing apparatuses; computer interfaces in the nature of units for connecting calorimeters, proximate analyzers, sulfur analyzers and electronic apparatuses to a laboratory computer or personal computer; sulfur interfaces in the nature of units for collecting and storing sulfur values from a sulfur analyzer and reporting said values to a calorimeter or to a computer interface upon request; and water handling units