J. F. Roux
Roux thought that the act of artistic creation resides in the decisions that the artist makes about what to leave out from the represented world, so that a painting is the product of the artist’s considered choices about what forms and colours to emphasise. There are some early paintings at Langebaan of fishing boats and later, from a trip with Margot to Sicily, of dwellings. Roux was also commissioned on occasion to paint pictures of farm houses. But on the whole, his landscapes represent nature in all its timelessness, stripped of any trace of human intervention.
Mineral redox buffer
In geology, a redox buffer is an assemblage of minerals or compounds that constrains oxygen fugacity as a function of temperature. Knowledge of the redox conditions (or equivalently, oxygen fugacities) at which a rock forms and evolves can be important for interpreting the rock history. Iron, sulfur, and manganese are three of the relatively abundant elements in the Earth's crust that occur in more than one oxidation state. For instance, iron, the fourth most abundant element in the crust, exists as native iron, ferrous iron (Fe), and ferric iron (Fe). The redox state of a rock affects the relative proportions of the oxidation states of these elements and hence may determine both the minerals present and their compositions. If a rock contains pure minerals that constitute a redox buffer, then the oxygen fugacity of equilibration is defined by one of the curves in the accompanying fugacity-temperature diagram. For other rocks with suitable minerals, oxygen fugacities can be calculated, and the redox conditions can be obtained by comparison to the fugacity-temperature diagram.