Wire, painted wood and aluminium mobile, 610 x 1613 x 343 mm (24 x 63 1/2 x 13 ½ in) fully extended; 610 x 1005 x 990 mm (24 x 39 1/2 x 39 in) contracted
Purchased from the artist through Annely Juda Fine Art, London (Knapping Fund) 1973
Essays in Movement: Reliefs by Mary Martin, Mobiles by Kenneth Martin, Institute of Contemporary Art, London, June-July 1960 (13)
Construction: England: 1950-60, Drian Gallery, London, January1961 (not in catalogue)
The Non-Objective World, 1939-55, Annely Juda Fine Art, London, July- September 1972, Galerie Liatowitsch, Basel, September-October, Galleria Milano, Milan, November-December 1972 (112, reproduced)
The Non-Objective World, 1914-55, Annely Juda Fine Art, London, July- September 1973, University Art Museum, University of Texas, Austin, October-December 1973 (93, reproduced)
Kenneth Martin, Tate Gallery, London, May-June 1975 (35, reproduced p.73)
Tate Gallery Report and Acquisitions, 1972-4, London 1975, pp.195-6, reproduced
Andrew Forge, ‘Notes on the Mobiles of Kenneth Martin’, Quadrum, 3, 1957, pp.94-6
Donald McNamee, ‘The Tradition of Constructivism by Stephen Bann’, Structurist, no.15/16, 1975/6, p.169
On embarking on making mobiles in the 1950s, Kenneth Martin explored several different means, of which the Screw Mobiles - such as Small Screw Mobile 1953 (Tate T00552) - became the most familiar. The Linkages were related to the Mobile Reflectors, his earliest examples, which relied on the balance of suspended forms following the work of Alexander Calder. Linkage used a simple method of suspension by threads to and from points near the end or off-centre on the bars. Of eight elements, the uppermost is a suspended bar of plain wood and the lowest a green-painted square plate made of aluminium. In between are six flat bars painted white. The upper pair of these carry wooden cubic weights and lower down are a pair with double-cubic weights (which the artist called ‘moving boxes’); these compensate for the bars’ suspension from an off-centre point. The use of bars served to reduce the gravitational droop which Martin had encountered in using dowels on the Mobile Reflectors; nevertheless, the wood of the upper pair of bars has warped as a result of the conflicting points of suspension. In view of the weight and the fact that ‘the wood of the bottom pieces had a tendency to break’, presumably at the end suspension points, the artist used aluminium for the lower elements. This adjustment to Linkage was the result of the construction of two preparatory maquettes, of which the artist destroyed one but retained the other.
In plan, the elements of Linkage establish two overlapping rectangles, an arrangement which allows the complete rotation of the counterbalanced bars suspended in the same plane. The green plate serves no structural purpose, but acts as the visual marker by which the motion of the mobile is traced. In his manuscript ‘On the Development of the Mobile’ dated June 1955, Martin discussed this role:
It is possible to make mobiles which develop interesting movements and to let chance play within a limited field, to let the air in the room create ovals, figure eights and so forth. But the resulting, desired, expressive movement and the machine which creates it are all part of the mobile, which must be an expressive unity in all its movements. For it cannot hide one movement and reveal another. And so, in the attempt I have made in this direction, I have distinguished the heroic unit by its colour from the rest of the machine, while the white panels, which control it, turn backwards and forwards and turning change their shape with their perspective.
Writing to the Tate about Linkage twenty years later, Martin rejected ‘the word heroic to describe the central suspended plate’, and considered the work, less hierarchically, as: ‘an experiment with a linkage which hung and balanced from two points with a central point that could describe a variety of horizontal curves’. By then, believing the movement of the whole to be more interesting than that of a part, he had omitted a corresponding plate from an enlarged motorised version in aluminium, made for the 1968 Cinétisme exhibition in Grenoble, where it was ‘lit by ultra-violet light’. Two years later, Martin used a rather different principle in making Standing Linkage, 1970 (Waddington Galleries).
The simplicity of the structure conceals the artist’s exploration of its underlying techniques. The term ‘linkage’ is used in mechanics for a closed chain of pivoted rigid components able to turn about one another. They are used for the transmission of motion, the alteration in the lengths of the bars establishing the relative speed and extent of the motion between a ‘driver’ and a ‘follower’. To artists, the most familiar is the four-bar linkage (i.e. a quadrilateral with pivoting corners) of the pantograph, used for copying or enlarging drawings. Martin read scientific and mechanical texts in the Science Museum Library, including Alfred Kempe’s How to Draw a Straight Line: A Lecture on Linkages (London 1877). Following Kempe’s diagrams, he made wall-mounted mobile reliefs which are visible in a 1955 photograph of his studio; in one of these four bars form a flexible quadrilateral linked to a circular plate by two longer bars. This six bar device recreates the straight-line mechanism named after the French engineer Captain Charles-Nicolas Peaucellier (who invented it in 1873), which is capable of describing a circle of any radius progressing to a straight line. Martin also consulted W.K. Clifford’s Elements of Dynamism (London 1878), which had shown that the ‘motion of a point round a circle could be split into two oscillations’, as the artist explained. Combining such theoretical and applied methods, he added that from this ‘simple harmonic motion’ it was possible to compose ‘open, repetitive sweeps of rods, but also completely bound together, though open, figures.’
Although not previously brought into the realm of art, Martin’s researches into the theories of the 1870s appear somewhat anachronistic in the 1950s. However, in a practical sense, they suited his combination of mechanical and hand-crafted work. It is notable that he used the simple four-bar plane linkage for the free hanging mobile, albeit causing the movement to be ‘more complex because I have used one linkage beneath another’. This was a recognition of the difficulty of making the free hanging mobile - in contrast to the earlier wall-mounted versions - as he acknowledged: ‘the problem was that I balanced it - enormously difficult - without fixed points’. Although Forge characterised the Linkages as ‘a relaxation from the hard concentration of the “Screws”’, Martin contested this, asserting that they showed ‘an interest in another aspect of movement and balance.’ He added that he concentrated on the Screw Mobiles because of a greater interest in ‘kinetic principles rather than in actual movement’.
 Martin, ‘On the Development of the Mobile’, dated June 1955, typescript copy Tate Gallery Archive 7040.2, p.12.
 Alfred Kempe, How to Draw a Straight Line: A Lecture on Linkages, London 1877, republished as part of the series Squaring the Circle and other Monographs, Chelsea Publishing Co., London 1903.
 Exhibition catalogue, Tate Gallery 1975, p.72.
 W.K. Clifford, Elements of Dynamism: An Introduction to the Study of Motion and Rest in Solid and Fluid Bodies, London 1878.
 Martin, ‘Invention: a lecture’, November 1956, typescript Tate Gallery Archive 7040.2, extracted in exhibition catalogue, Tate Gallery 1975, p.9.