In a Congolese State of Mind.

Technology reveals what David Livingstone was thinking and doing during those lost years:

In the last years of his life when he was in remote parts of Africa, Livingstone had run out of writing paper and had to scrawl his letters on used newspapers and pages from books using ink from berries. Most of the letters are now virtually unreadable and historians have had to rely on versions that were heavily censored by Livingstone's friend and biographer Horace Waller. But Livingstone's true thoughts are being revealed by scientists using techniques that enhance the ink while suppressing the background print.

The first deciphered letter, written on 5 February 1871 from a village called Bambarre in what is now the Democratic Republic of the Congo, has just been made public in the first stage of a project to reveal the contents of Livingstone's previously unpublished final diary from 1870-71.

Waller, to whom the letters were addressed, omitted (at his friend's request) some references to Livingstone's ill health and weaknesses. Livingstone wrote to him: "I am terribly knocked up but this is for your own eye only: in my second childhood [referring to his lack of teeth – several of which he extracted himself] a dreadful old fogie. Doubtful if I live to see you again."

Despite his ill health in the midst of a cholera epidemic that devastated the local population, he wrote of his determination to complete his search for the source of the Nile: "Well I am off in a few days to finish with the help of the Almighty new explorations."

The letter also includes Livingstone's thoughts on the "awful traffic" of the slave trade which he said could be "congenial only to the devil and his angels". Fiercely competitive, he was critical of the achievements of fellow explorers Samuel White Baker, Richard Burton and John Hanning Speke. The Scottish missionary also talked about the prospects for commerce and Christianity in Africa, gave details of lakes and rivers in central Africa and expressed his disgust with the British government's policies in Africa and the Middle East.

It is thought the Bambarre letter was only delivered to England in 1872 by the New York Herald reporter Henry Morton Stanley who met Livingstone in late 1871 with the words: "Dr Livingstone, I presume?"

Morton had been despatched by his paper to find Livingstone, who had been lost to the outside world for six years. Livingstone died at the age of 60 in 1873 in Zambia from malaria and internal bleeding caused by dysentery. He suffered extreme ill health in the final years of his life, including horrific tropical ulcers on his feet and legs.

Eventually, the full text of the letters will be posted at the Livingstone Online website. Photo: Callum Bennetts/AP