A HARROWING account of the massacre of 400 slaves, written by the famed Scottish explorer David Livingstone, can be read for the first time, the National Library of Scotland has revealed.

A diary written by Livingstone 140 years ago had been unreadable as it was penned with ink made from berry seeds on the pages of an old newspaper and had deteriorated until it was virtually invisible.

However, an international team of experts has utilised new technology, called spectral imaging, to recover Livingstone’s words, written in 1871, for the first time.

The 18-month project uncovered Livingstone’s personal account of the “unspeakable horror” of the slave trade.

The account helped change history. Livingstone told the journalist Henry Morton Stanley of the incident, and his report of the massacre helped force the British Government to end the East Africa slave trade.

The manuscript had been preserved by the National Trust for Scotland’s David Livingstone Centre in Blantyre, and studied by Dr Adrian Wisnicki and Dr Debbie Harrison of Indiana University of Pennsylvania and Birkbeck College, London, and research assistant Kate Simpson, of Napier University in Edinburgh.

The diary showed Livingstone was horrified by the massacre, as three Arab slavers with guns entered the market in Nyangwe, a Congolese village, where 1500 people were gathered, most of them women.

“Fifty yards off two guns were fired and a general flight took place ... shot after shot followed on the terrified fugitives ... great numbers died ... it is awful ... terrible, a dreadful world this,’ wrote Livingstone.

“As I write, shot after shot falls on the fugitives on the other side [of the river] who are wailing loudly over those they know are already slain ... Oh let thy kingdom come.”

Dr Wisnicki, who led the project, says there is evidence in the diary that suggests members of Livingstone’s party might have been involved in the massacre.

“Livingstone seems to have considered this possibility and this, together with his failure to intervene, appears to have left him with a profound sense of remorse,” said Dr Wisnicki.

“In copying over the 1871 diary into his journal, Livingstone decided to rewrite or remove a series of problematic passages. It’s taken 140 years to discover Livingstone’s original words and reveal the many secrets of the original diary.”

Dr Wisnicki said many of the diary passages are different from the accounts in The Last Journals of David Livingstone (1874), edited after the explorer’s death in 1873 by his friend, Horace Waller.

“Livingstone would never have published this private diary in his own lifetime,” said Dr Wisnicki. “In particular his attitude to the liberated slaves in his entourage is one of disgust -- an attitude greatly at odds with his public persona as a dedicated abolitionist.”

Dr Wisnicki said he believed that the publication of the diary will change the way some may look at Livingstone. “Instead of the saintly hero of Victorian mythology, the man who speaks directly to us from the pages of his private diary is passionate, vulnerable, and deeply conflicted about the violent events he witnesses, his culpability, and the best way to intervene -- if at all,” he said.

The team illuminated the manuscript with successive wavelengths of light -- starting with ultraviolet, working through the visible spectrum, and ending with infrared, while processed digital images enhanced the selected text.

Livingstone’s 1871 Field Diary -- funded by the British Academy and the US National Endowment for the Humanities -- is a free online public resource published by the UCLA Digital Library Program in Los Angeles.