Variable Screw

The four brass strip parabolas in this rotating Variable Screw mobile can be rearranged and rebalanced on its threaded vertical rod, introducing further variations of movement. It is part of a series of mobiles that Kenneth Martin developed in the mid-1960s which use the three elements of parabola, circle and vertical line to explore the complexity of motion. [1]

In 1968 Martin wrote in detail about Variable Screw and the crucial role of change and movement in this series of mobiles in an article for the art journal Leonardo. [2] For Martin, change was integral to the process of constructing Variable Screw and to interacting with it as an end-product. He believed that restricting both processes to certain rules heightened awareness of the expressive energy of change and movement.

‘The parabolas, four in number, are different in width but not thickness. They are fixed to the cylinders at different positions determined by the theoretical rolling and stopping of the latter. Each parabola with cylinder has different characteristics from the others and one of these has to do with weight. As this becomes centred on the cylinder when the latter is placed on the threaded rod, each bar becomes more or less of a cantilever. It is necessary to balance the whole, suspended system and so the participator becomes involved, not only in the limited and direct choice of position within the system, but also in the feeling of balancing, however simplified that action may have been made.’ [3]

Kenneth Martin loaned Variable Screw to the University of East Anglia in 1968 for the exhibition ‘Art and the Machine’, organised by Alastair Grieve at the recently opened University Library. Later that year, UEA acquired this important work from Kenneth Martin, along with his painting Black Sixes, for the University’s pioneering collection of twentieth century abstract and constructivist art. [4]

Lisa Newby, November 2020

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