The diary of a sailor depicting his first hand accounts of the slave trade, is to be put on display at a museum.
The accounts will be on display from 3 February
The 19th Century document belonged to Midshipman Henry Binstead who kept a record of his time in the Royal Navy off west Africa in 1823-1824.
His great great granddaughter Rosa Lee, from Maidenhead, Berks, gave the diary to the Royal Naval Museum, Portsmouth.
The diary is part of an exhibition marking the bicentenary of the abolition of transAtlantic slavery.
An act of Parliament banning the transportation and capture of slaves came into force in March 1807.
Henry Binstead's accounts spanned his time aboard the HMS Owen Glendower part of the navy's West Africa Squadron, which patrolled the African coast to stop the illegal slave trade.
In his diary, 28-year-old Binstead wrote: "Observed many large canoes, one of which I went in chase of, on my coming up with her the whole crew jumped overboard and I fear they have met a watery grave, these poor wretches were fearful we were going to make slaves of them."
Midshipman Binstead, originally from Portsmouth, kept account of the human suffering he witnessed when an illegal slave ship was intercepted.
"I never witnessed a more horrid description than my messmates gave me of the wretched state they were in [320 men, women and children] onboard actually dying 10-12 a day owing to the confinement below.
"All the men are in irons and women under them by a small partition."
Rosa Lee, 82, who inherited the diaries from her mother, said: "I am so glad I kept the diaries and they are of interest and that they have found a natural home."
The diaries will be on display as part of 'Chasing Freedom: the Royal Navy and the Suppression of the Transatlantic Slave Trade' on display from next weekend.