The design of the torch used in the relay to the Games changes for each Games. They may be designed to represent a classical ideal, or to represent some local aspect of those particular Games. Some, such as Albertville in 1992 and Turin in 2006 have been designed by famous industrial designers. These design-led torches have been less popular than the more classical designs, the Turin torch in particular was criticised for being simply too heavy for the runners. The torch for the 1948 London Olympics was designed by architect Ralph Lavers. They were cast in Hiduminium aluminium alloy with a length of 47 cm and a weight of 960 g. This classical design of a long handle capped by a cylindrical bowl re-appeared in many later torch designs. The torch used for the final entry to the stadium and the lighting of the cauldron was of a different design, also a feature that would re-appear in later years. This torch did not require the long distance duration or weather resistance of the other torches, but did need a spectacular flame for the opening ceremony. At the Melbourne Olympics of 1956, the magnesium / aluminium fuel used for the final torch was certainly spectacular, but also managed to injure its holder. Runners were also burned by the solid-fueled torch for the 1968 Mexico Games. The fuel used for the torch has varied. Early torches used solid or liquid fuels, including olive oil. For a particularly bright display, pyrotechnic compounds and even burning metals have been used. Since the Munich Games of 1972, most torches have instead used a liquefied gas such as propylene or a propane/butane mixture. These are easily stored, easily controlled and give a brightly luminous flame. The number of torches made has varied from, for example, 22 for Helsinki in 1952, 6,200 for the 1980 Moscow Games and 8,000 for the London 2012 Games. In transit, the flame sometimes travels by air. A version of the miner's safety lamp is used, kept alight in the air. These lamps are also used during the relay, as a back-up in case the primary torch goes out. This has happened before several Games, but the torch is simply re-lit and carries on. The torch has been carried across water. The 1968 Grenoble Winter Games was carried across the port of Marseilles by a diver holding it aloft above the water. In 2000 an underwater flare was used by a diver across the Great Barrier Reef en route to the Sydney Games. In 2012 it was carried by boat across Bristol harbour in the UK and on the front of a London Underground train to Wimbledon. The latest torch is designed by Edward Barber and Jay Osgerby for the 2012 London Games. Despite a deeply cynical response to the logo and mascots of the London Games, this torch design appears to have been well accepted in the UK and internationally.
