Excerpts from Joseph Conrad's The Congo Diary (1890). Stylistically, its staccato sentences are the opposite of the elliptic, questing prose of his later Heart of Darkness (1902), but it's an important precursor in content and emotion. Page numbers are from Joseph Conrad, Heart of Darkness, ed Robert Hampson, Penguin, 1995.
Prominent characteristic of the social life here [in Matadi]: People speaking ill of each other.- [150, cf HOD 45-6]
Harou giving up. Bother. Camp bad. Water far. Dirty. At night Harou better. 
... the dead body of a Backongo. Shot? Horrid smell. [152, cf HOD 39]
Saw another dead body lying by the path in an attitude of meditative repose.- 
Water very indifferent [...] Village invisible - [...]
Afternoon very close
Night clear and starry. 
Row with carriers. - No water. At last about 11/2 pm camped on an exposed hill side near a muddy creek. No shade. Tent on a slope. Sun heavy. Wretched. [...]
Night miserably cold.
No sleep. Mosquitos - [...]
The country presents a confused wilderness of hills land slips on their sides showing red. Fine effect of red hill covered in places by dark green vegetation.
Most comfortable and pleasant halt.
Stayed here until the 25th. Both have been sick. - Mostly kindly care taken of us. Leave with sincere regret. 
Left camp at 7h after a good night's rest. Continuous ascent; rather easy at first. - Crossed wooded ravines and the river Lunzadi by a very decent bridge - [...] Looking very well - Bad news from up the river - All the steamers disabled. One wrecked. [cf HOD 40] [...]
On the road to day passed a skeleton tied-up to a post. Also white man's grave - No name. heap of stones in the form of a cross.
Health good now - 
Harou arrived very ill with billious attack and fever. - Laid him down in govt shimbek - Dose of Ipeca. Vomiting bile in enormous quantities. At 11h gave him 1 gramme of quinine and lots of hot tea. Hot fit ending in heavy perspiration. At 9pm put him in hammock and started for Kinfumu - Row with carriers all the way. Harou suffering much through the jerks of the hammock Camped at a small stream -
At 4h Harou better. Fever gone.- [...]
Expect lots of battles with the carriers to-morrow - Had them all called and made a speech which they did not understand. They promise good behaviour [cf HOD 40]
Congo very narrowe and rapid. Kinzilu rushing in. [...]
Harou very little better.
Self rather seedy. Bathed.
Luila about 60 feet wide. Shallow [...]
Row between carriers and a man stating himself in govt employ, about a mat. - Blows with sticks raining hard = Stopped it.
Harou not very well. Mosquitos - Frogs - Beastly. Glad to see the end of this stupid tramp. Feel rather seedy.
Sun rose red - Very hot day - Wind Sth 
More notes on Heart of Darkness to follow...