What has sawing a lady in half to do with global warming?

At this time of year, exactly 70 years ago, I was taken to my first exhibition of professional conjuring. The magus called himself Dante — he was Danish-American and his real name was Harry Jansen. He had an amazing moustache and beard, wore dazzling evening dress and a red satin-lined cloak, and performed his tricks at lightning speed: his slogan was ‘15 sur- prises in 15 seconds’.