Immaterial: Brancusi, Gabo, Moholy-Nagy At Kettle's Yard, Castle Street, Cambridge, until 14 March
Kettle's Yard's look at immateriality in early modern sculpture begins, quite properly, with a spellbinding vanishing act. Three photographs by Eugene Limet show one of the most corporeal sculptures of the late 19th century, Rodin's Burghers of Calais.The five men have volunteered their lives to save their city from the English who are holding it siege, and we see them walking to their deaths, their clothes ragged and their ankles shackled. In the last moments of their life they seem at their most fleshy, and yet in Limet's photographs they are already fading from view, the grainy surface texture of his prints reducing them to mere shadow.
Limet's photographs are a very graceful introduction to this enthralling show, and they properly suggest the full breadth with which notions of immateriality were considered in the early 20th century. The bulk of the exhibition concentrates on technological understandings rather than philosophical - hence the Constructivists Naum Gabo and Lßszl¾ Moholy-Nagy are central - yet it also demonstrates that, even when artists were beginning to confront the scientific, they often did so with self-consciously artistic means. If Einstein and Rutherford were changing perceptions of the world, ancient myths like that of Prometheus, and Leda and the Swan, were still offering artists a framework with which to explore those ideas.
Limet's photographs are also a fine introduction to the works by Brancusi that follow them. Brancusi, the Hungarian peasantsage, might be a strange bedfellow of enthusiastic Modernists, particularly since the four sculptures on view here, among them Cock from 1924 and Fish from 1926, only emphasise his attachment to the land.
Yet, as weighty as his bronzes are, Brancusi buffed their surfaces to such a reflective gleam that light seems to glide over them and their solid forms dissolve in fluidity.
Photography was important to Brancusi in capturing the qualities of glare and dissolution that he wanted from his surfaces, and the examples here are a good illustration of that.
Generally, photographs of sculptures carry more weight here than the sculptures themselves, and that seems reasonable, given that the artists were as interested in the peculiarities of perception as they were in constructed form.
A lot of Constructivist sculpture can be rather underwhelming in any case; 70 years or so after its execution, its bold vision tends to look grubby. Kettle's Yard has a pristine 1977 remake of Moholy-Nagy's Spirals, a serene tangle of translucent perspex that was first realised in 1946, but today it still seems like the model for a much more perfect construction.
In works of such translucency and ethereal grace, just a smudge of glue or a visible screwhead will tarnish them; their play with space is also so delicate that even the most unobtrusive display cases and barriers disrupt them. Ultimately, works like these make immateriality seem less like a phenomenon to be manifested than an aspiration to be expressed.
If ever Moholy-Nagy did find the perfect form to match his inspiration, it was in his kinetic art masterpiece Light-Space Modulator. And, once again, it really isn't much to look at, just an odd, box-like contraption of moving metal parts. In motion, however, and with the spotlights shining, it gives off the most mesmerising play of changing reflections and shadows. Kettle's Yard hasn't the precious thing itself but does have Moholy-Nagy's 1932 film of it in action. It is the show's concluding statement, and it's a gorgeous thing: so terribly old-fashioned, and yet so much more optimistic about technology than any of us seem to be today.
Morgan Falconer is a journalist in London