IN A futuristic art gallery which Carlos Slim opened last year in Mexico City, visitors can enjoy, among other things, a hall of rare coins and share certificates. Sometimes art speaks louder than words.Mr Slim is the richest man in the world. According to Forbes, he and his family have amassed a comfortable nest egg of $63 billion. (Bill Gates would be richer had he given away less of his stash, or Mr Slim more of his.) In Mexico Mr Slim is a giant: his companies account for more than a third of the stockmarket.The Slim fortune was made in telephony. After growing moderately rich from property, mining and other businesses, Mr Slim, the son of a Lebanese immigrant named Salim, bought Telmex, Mexico’s state-run telephone monopoly, in 1990. Telmex still has 80% of Mexico’s landlines, and about 75% of its broadband connections. Telcel, its sister company, has 70% of the mobile market. Both now belong to América Móvil, a Slim venture which has spread across 18 countries in the Americas and is the biggest or second-biggest player in all but three. With nearly 250m subscribers, it is the world’s...