Charles Darwin 's five-year voyage in HMS Beagle proved to be one of the most important scientific journeys ever made. It was more than a great adventure. It was also a voyage of the mind. As Darwin not only kept a journal while on board, but also wrote his autobiography later in life, it has been possible to re-tell much of the story in his own words.

HMS Beagle, with the young Charles Darwin aboard as ship's naturalist, arrived in Salvador, Brazil, in February 1832. At once, the miseries he had endured from seasickness were forgotten, as he lost himself in the luxurious wonderment of the rain forest.

After facing the fearful gales of Cape Horn the Beagle turned north into the quieter waters of Tierra del Fuego. On board Captain FitzRoy had three Indians, whom he planned to return to their homeland to found a Christian colony. But from the start, Darwin was filled with misgivings about the success of the experiment.

In September 1833 Darwin set out to cross the Argentine pampas, heading for Buenos Aires. Immediately he found himself in the midst of a bitter struggle between the local Indians and the forces of General Rosas, who were engaged in a policy of extermination. ' I was made vividly aware of the relentless struggle for existence going on around me. Who would have believed, in a Christian country, that such atrocities could be committed? '

In 1835 an earthquake destroyed the town of Concepcion in Southern Chile. The effect of it was felt on board the Beagle, and a few days later Darwin witnessed the devastation for himself. It confirmed his view that the whole range of the Andes had been pushed up from the bed of the ocean.

On the Galapagos Islands, Darwin observed subtle differences between the inhabitants of one island and those of another. But he nearly missed the significance of the little brown finches. Some had beaks thin enough to pick up seeds from the hard ground; others had beaks thick enough to crack a nut. Here was the clue which led him directly to the theory of natural selection.

When The Origin of Species was first published, it was denounced as the work of the devil from pulpits up and down the land, and banned from university college libraries. Scientific opinion and Christian doctrine were in open conflict about one of the most profound and basic of all mysteries - the beginnings of life on our planet. The great debate reached its climax at the famous Oxford Meeting of the British Association in 1860.