By 1921 Gabo had moved away from figuration to pure abstraction. In the Realistic Manifesto, published in Moscow in 1920, he and his brother Antoine Pevsner announced a new form of art based on space and time. It was, they claimed, an affirmative response to the new world order that had emerged over the last twenty years. They argued that the radical disturbance of old certainties in the sciences (particularly physics), in society (for example the Great War and the Russian Revolution) and in art (notably Cubism and Futurism), had so weakened established perceptions of reality that a new model was needed for understanding existence. They maintained that since life happens in real space and time, only art that incorporated these elements could contribute to a constructive understanding of it.
In Construction in Space: Diagonal a complex arrangement of interlocking linear and curvilinear components is suspended within an open frame of two intersecting rectangles. The clear glass and yellowed celluloid elements allow the viewer to see the various layers of the sculpture simultaneously. The experience of looking through the construction is punctuated by discreet opaque accents such as the thin metal rods. The solidity of these accents provides a counterpoint to the virtual dematerialisation suggested by the clear glass and celluloid.
The precision with which the elements of Gabo's constructions were made, and the manner in which they were arranged, encouraged comparisons with scientific instruments and modern architecture. Indeed, this piece was originally exhibited at the Museum for Arts and Science, Brooklyn in 1926 as Construction for an Observatory. However, like most of Gabo's projects for public buildings and monuments it was not realised.
Probably conceived in 1921 while Gabo was living in Russia, it is likely that Construction in Space: Diagonal was made in Germany after his move there in 1922. The current title was only conferred on the work at the Gabo: Konstruktive Plastik exhibition, Kestner-Geselleschaft, Hanover in 1930. A photograph published in 1931 (Justus Bier, 'Gabo', Die Form, year 6, no.12, 15 December 1931, pp.465-7) suggests that the current metal verticals may originally have been in transparent glass, though when the work was illustrated in 1957 (Gabo: Constructions, Sculpture, Paintings, Drawings, Engravings, London 1957, reproduced p.182, fig.16, as Tower 1921-22) these elements were opaque. After the artist's death in 1977, the piece was rediscovered largely intact in his attic. It has since been reconstructed by Charles Wilson, Gabo's studio assistant from 1960 to 1977.
Gabo: The Constructed Idea: Sculpture, Drawings, Paintings, Monoprints, exhibition catalogue, South Bank Centre, London 1987, reproduced p.12
Steven A Nash and Jörn Merkert, Naum Gabo: Sixty Years of Constructivism, Munich 1985, reproduced p.209
Naum Gabo: The Constructive Process, exhibition catalogue, Tate Gallery, London 1976