I had a brief chat to James about his trip to Berlin � we spoke mainly about his visit to Sachsenhausen which made big impression. I said that the only Nazi relics that I had seen were much more decorative. I was on my way to see Stephen Bates for lunch. He took me for a circular canal walk around the centre of Birmingham � just the kind of thing I need to do more of. But its much more fun when you have got someone to gossip to. I drove back listening to P Funk.

I found myself back thinking about whole number ratios. I was surprised to find that the tritone can be simulated by the ratio of 17/12 � 17 squared is 289 which is close to twice 12 squared � 288. I need some new batteries for my calculator.

The Observer says that there will be a Bill Viola exhibition at the National Gallery starting at the end of October There is also a work on display at the Oxford Modern Art Museum which includes some Karen Carpenter performances. So much to see.

I re-read the Mike Kelley interview in the Wire and discovered that he has played in a band with Baudrillard. The more I dig the more I find quite deep latent connections with the pomo.

On Sunday night I listened to the Radio 3 feature on the Tropicalia movement in Brazil � something I knew odd bits and pieces about. I hadn�t realised that The Beatles� Sergeant Pepper was such a strong and immediate influence on the leaders of the movement especially in terms of combining all kinds of music together, not least the avant-garde. I took the trouble to record the talk to CD off air. The leaders of the movement admired the founders of bossa nova but disliked the social limitations of that music and wanted to be more radical but also appeal to a wider range of people both in Brazil and across the world. The ideal of freedom was less a political objective but more a personal and artistic one but even so the came into conflict with the military dictatorship because they were novel and using mass media. Roger Duprat was the partner in the project who bought in knowledge of Cage and Stockhausen.

One step more on the Brazilian theme � last night there was a broadcast performance at the from the Niemeyer pavilion outside the Serpentine Gallery. Niemeyer is one of the founding fathers of modern architecture and designed lots of the most famous buildings in Brazilia � he is now over 90. I was going to write about him when I went to the Cindy Sherman exhibition but didn�t manage it. The broadcast was improvised electronic music � not especially to my taste. I need to think harder about this stuff.

I scanned into the computer the three watercolours that I did in Cornwall and started amending them using the available editing tools in the Microsoft that came with the PC. I was surprised how effective the paint simulations are. I must ask Mark about the new software that he is using.