Compensation

'Sorry , the members' terrace is closed because they're working on the tower. There's a danger of falling debris'.

Oh no! The best thing about the Tate Modern is the sixth floor terrace opposite St Paul's, where you can sit and write and watch people crossing the Millennium Bridge. The weather was perfect for it.

So that was disappointment number one. Disappointment two was the exhibition we'd come to see: Roni Horn aka Roni Horn.

The drawings, sculptures and photos were intriguing but not engaging; an 'ant farm' consisting of black earth pressed between two plates of glass in a frame; pairs of metal balls placed individually in adjoining rooms, ditto two blunt-ended cones, like giant copper ear-plugs; various resin cubes and shiny-topped grey and black discs ; a room full of almost identical portraits of a girl's water-splashed face; pictures of Iceland with people in hot lakes and a bleak cabin room like the set for a bleak Scandinavian film; 49 photos of the artist's 12 year old niece pulling faces. The miniature booklet given to us at the entrance was unenlightening, rambling in convoluted language about identity and the relationship created by spaces and obsession with pairs.

I didn't dislike all of it. In some large frames a long red strip had been cut up and the curves reassembled in vague shapes , so that to look at them was like guessing at cloud forms or those inkblots used for psychological testing. Two Snowy Owl portraits side by side reminded me of newspaper 'spot-the-difference' puzzles. Monochrome photos of the murky Thames had the novelty of little numbers scattered across the surface, matched to gloomy philosophical and literary footnotes.

The highlight of the exhibition for me, although R said he didn't notice it, was a transparent cube the size of a coffee table that could have been cut from a giant tablet of raspberry jelly. It glowed in the light from the gallery's tall windows overlooking the Thames. The other pleasant aspect was that the rooms were almost deserted because the crowds were milling about in the public areas or in the excellent Rodnikov and Popova exhibition.

I looked and looked at the exhibition postcards but couldn't take to a photo of crumpled gold foil wrapping papers or a miniature medieval map of Iceland. I'd like to go there sometime, though, to take a plunge in those hot lakes. I came away feeling that recent months of gallery-going hadn't really helped me empathise with such introspective artworks. My feet ached and Waterloo Station seemed far away.

But all that was soon forgotten. What a wonderful surprise, to come across this spendid show of Polish wildlife photos, in a perfect setting: under the trees near the National Theatre.

Roni Horn aka Roni Horn: http://www.tate.org.uk/modern/exhibitions/ronihorn/default.shtm

Southbank events (trawl down for Wild Poland Exhibition) :http://www.southbanklondon.com/page/whatson/