used for reduction, but with less success; Stedman, unpublished).
The air in the tube is displaced with CO2 and N2 by the
Hungate technique and the tube is stoppered (Hungate et al.
1966). A cap is placed on the tube and the assemblage autoclaved.
A gas phase of 160 kPa of CO2 and 1 kPa of H2S has also
been used successfully (Prangishvili 2006).