Les Apostrophés, Barbican Pit, London

Juggling to dream to, no drum roll required

What goes up, must come down – but not, in this case, before creeping across a pair of broad shoulders, toying awhile around the nape of a man's neck, and rolling down the length of his arm. Part of the 31st London International Mime Festival – which has defied economic reason and sold out – L'Ecume de l'Air is a curiously low-key affair: a juggling and music act that asks for quiet contemplation, not drum rolls.

Its title translates awkwardly: Spume of the Air? Foam, froth, spray? Rarely does juggler Martin Schwietzke project objects into space with any force. The pervading dynamic is floating and drifting, which, when you think about it, is a perverse thing to ask of a set of 10cm diameter balls. What's more, Schwietzke likes to keep things intimate, small-scale. He'll use just three projectiles, where a showier performer would use six, but gives the impression of having a personal relationship with each one.

During a sequence in which balls pass not just from hand to hand, but between the crook of an elbow, alternate temples, and even that little hollow in the collarbone, one occasionally drops to the floor. Standard practice is to ignore mistakes. Schwietzke, though, stops dead and gives each escapee a stern, reproving look, as if to say: "I always knew you were a bad 'un. Don't show your face round here again". And after reaching into a snake-charmer basket for a new ball, he gives the replacement a silent warning: "And you, just behave yourself, OK?"

The other half of the duo is double bassist Michel Bismut, a cheerful, barefoot presence who plucks and saws and croons his way through baroque, contemporary atmospherics, rock'n' roll, and Tunisian pop, but is most obviously in his element playing jazz. Not everything in this show quite comes off, however. The final sequence is badly misjudged, as Schwietzke drifts about balancing a large spherical balloon on a stick. Lit to look like the moon in cold blue space, it's lovely, but soporific. Juggling as tranquilliser clearly has potential.