'Message in a bottle' for auction

The letter is expected to fetch about £20,000

A message in a bottle left at an African river by Scottish explorer David Livingstone has been unveiled ahead of an auction later this year.

The note was written in May 1859 and requested urgent provisions from any passing ships.

Livingstone's letter was found a month later by a Royal Navy patrol vessel and bought by Quentine Keynes in 1957.

It will go on sale alongside a collection of 800 travel and history books owned by the Keynes family.

The explorer's letter describes his trip up the Zambezi and Shire rivers in Africa and tells in detail of his discovery of Lake Shirwa, in what is now Mozambique.

He also asked that "salt provisions" be left at the Zambezi mouth for the crew of his paddle-steamer, after a ship carrying supplies failed to show up there for a pre-arranged meeting.

'Dr Livingstone, I presume'

It forms part of a collection of 800 travel and natural history books and documents being sold by the family of Keynes, the great-grandson of Charles Darwin.

The collection, being auctioned by Christie's in London from 7 April, is expected to fetch about £3m, with Livingstone's letter valued at £15,000 to £20,000.

The note requested urgent provisions from passing ships

Also being sold is a document signed by Livingstone and reporter Sir Henry Morton Stanley.

The latter became famous for the words: "Dr Livingstone, I presume" after tracking down the explorer when he went missing on an expedition to find the source of the Nile.

Another Livingstone letter describing rival adventurer Sir Richard Burton as "an awful ruffian" is also going under the hammer.

Livingstone, born in 1813 near Glasgow, was the first European to discover the Zambezi and the Victoria Falls, which he named for his Queen.

He went to Africa as a missionary and tried and failed to find the beginning of the Nile. But his adventures earned him national hero status.

Following his death on 30 April, 1873, Livingstone's heart was buried in Africa as he had requested, but his body was returned to England and buried in Westminster Abbey.