Unsitdownable

Cube Gallery, Manchester / Jeffyre Museum, London

One, at the Cube Gallery, Manchester, is a travelling exhibition from the Vitra Design Museum. It offers 100 Chairs - 100 Years (that is, chairs 1905-2005), and the objects are presented as 'masterpieces' of design.

While that word once denoted objects demonstrating an apprentice's mastery of his craft, it is now code for 'the greatest! Admire!'. Accordingly, the chairs are put on parade. They are in chronological sequence, divided by date panels every decade or so.

Each occupies a unit of space on a glass-and-metal rack system (designed by Dieter Thiel), which, while it can be flexibly combined to fit different spaces, effectively places each chair in an identical three-dimensional frame, emphasising the chair-as-art.

Each chair has a tactful little label (technical details, but no comment), and, in this Manchester show, a somewhat more prominent stand-up Perspex label informing us which of many sponsors from the city's design community has favoured this particular chair. These paired labels give a feeling of mixed messages.

There are also text-and-picture panels, relating to the chronological periods into which the exhibition is divided. These are somewhat randomly arranged on the walls. Solid essays of 500-plus words, summarising the political, social and technical background, are quite a lot to take in.

The pictures, intended to supply context, are mostly postcard size (requiring that you go up close), and their small, short captions are separated from them at the foot of the panels (requiring that you squat).

Supposing you want to learn about a Frank Lloyd Wright chair, you must first locate one in the sequence of chairs, by squinting at labels until you spot the appropriate name. Then you must resort to the panels, bobbing around between captions and pictures. Then you must puzzle out the connections for yourself.

It might be easier to buy the accompanying book (£14.99, with information and pictures smoothly marshaled on double-spreads), and sit comfortably with it at home. Incidentally, a chair is first and foremost a machine for sitting on, but in this exhibition you cannot sit on a chair. Looking is all.

At the Geffrye Museum, London, there is a three-part exhibition, extending across two rooms and the stairwell in the new building. One part deals with 'The English Regional Chair' (18th-19th century) from Bernard Cotton's collection.

Thirty-six chairs are displayed (by the Richard Greenwood Partnership) in groups, according to where they were made. The chairs rest on standard plinths, but the height of the plinths is varied, so that the exhibition presents a picturesque rather than regimented spectacle.

Behind each group of chairs is a very large blow-up of a painting or photograph, providing context; alongside is a large text-and-picture panel (designed with just the right mixture of order and diversity by Sally McIntosh).

In front of each chair is a label on a stand, with smaller text and pictures. There is, then, a judicious grouping and gradation in the elements of the display, which gently assist perception and comprehension. What we learn is quite precise: how to do a kind of connoisseurship.

It soon becomes fun to spot the bell-shaped seat, the vasiform splat, the comb back, the curved stretcher. We perhaps will not choose Cotton's massive book on The English Regional Chair (£49.50) as bedtime reading, but the exhibition itself succeeds in giving us an elementary grasp of the subject.

Also, we can sit on modern reproductions of the two basic types of popular chair, we can handle parts, construct and dismantle a chair, pore over specimens of woods, and answer 'lift-the-flap' questions. These features are not innovative, but are well integrated in the exhibition.

A second display, 'Sit', offers us contemporary chairs that 'subvert traditional forms'. The design (by Pat O'Leary) rests the chairs on an irregularly shaped plinth, wittily lit by reading lamps.

Some of these chairs at once provoke an empathetic reaction (one seems to be two chairs hugging each other, another adopts the shape of a belly-button), but we need help with most of the jokes, and this is provided on Kate Kneale's A4-sized text-and-picture labels.

You pick them up, and a chain retracts them by gravity when you've read them. There are also some chairs that you can sit on, and the FunKtion Objects (polyurethane moulded shapes) by Hurtado and Feo draw children irresistibly to chuck them around.

A third section, 'Choice Chairs', provides panels in which eight London designers are pictured in their favourite chairs, with their comments. This is a sort of Hello!-magazine-style interlude, but makes us feel acquainted with these designers, while, in contrast, the designer-sponsors at Manchester, though named, remain a mysterious inner circle.

It will have become obvious that for this visitor one of the two exhibitions seems more successful than the other. This is not just a result of institutional ethos. An exhibition in an architecture gallery might be expected to be more puristically abstract than one in a social history museum - but both the Cube and the Vitra Museum claim to want to explain the social context of design.

Nor does the difference result only from aesthetics - though it springs to the eye that the Vitra exhibition is disciplined by designer's grids, while the Geffrye displays are more free-form (appropriately, perhaps, in a Nigel Coates building).

The difference lies primarily in the quality of communication. There is a certain aloofness in the Vitra exhibition. Various visual and verbal constituents are presented on a take-it-or-leave-it basis. This could be claimed as a virtue, on the grounds that it offers visitors a free choice of various routes of access to the subject exhibited; conversely, it could be said that it fails to add up.

In the Geffrye displays, however, coherent visual discourses have been imaginatively composed and invitingly presented - which is surely what exhibition design is all about.

Anthony Burton is the author of Vision & Accident: The Story of the Victoria and Albert Museum