Today is the 200th anniversary of the birth of this famous scientist and writer, best-known for his prodigious four-year journey across South America and for the Pacific current which bears his name. Foremost among the many Latin-American nations to celebrate this event will be Mexico, visited by Humboldt in 1803-4 and where he is revered as one of the founders of the country's independence from Spain.

In this birthday tribute Robert Cundy follows Humboldt's route across Mexico from ocean to ocean, Acapulco to Vera Cruz. He descends silver mines and climbs recently erupted volcanoes to present a portrait of a country whose diverse landscape and mysterious past presented an irresistible challenge to a scientist and humanist fascinated by everyone and everything.

When the British left India in 1947 it is said that they left behind them 'some of their customs, a little of their culture, and very occasionally a few of their kind.' Left-Over Raj is the story of a few of the kind who remained behind in the city of Calcutta - half a dozen individuals who chose to stay behind feeling that they could accept their new role in an independent India, and perhaps contribute something. They are people like Captain 'Dinkie' Fownes, a race-horse trainer; John Crossley, who makes tea-chests and distributes milk to 1,000 slum children every day. Tony Lucey runs his own little factory; Desmond Doig works for the Calcutta Statesman.