July 31, 1831

Paul Belloni du Chaillu (July 31, 1831 to April 29, 1903) was an explorer who wrote many books and is the subject of more than one biographical study, like
Paul Du Chaillu, gorilla hunter, by Michel Vaucaire (1930)
The Farther Frontier: Six Case Studies of Americans and Africa by Lysle E. Meyer (1992),
and The Species Seekers by Richard Conniff (2011).
And recently released: Betweeen  Man and  Beast: An Unlikely Explorer, the Evolution Debates, and the African Adventure That Took the Victorian World by Storm,  by Monte Reel (2013).

Du Chaillu's own books include his observations of pygmies (their existence had been considered dubious before his reports): The Country of the Dwarfs (1874 ). Also
The land of the midnight sun (1881) (Du Chaillu gathered evidence that the Vikings had influenced the British Isles, then a shocking idea) and
In African forest and jungle (1903). These are just a few of his own books.

In a book review  (April 4, 2013)  of the last biography mentioned above, an article written by David Quammen, then, it is a little surprising to learn that du Chaillu is still a figure of some mystery. 

It’s easier to say who ...[du Chaillu] wasn’t. He wasn’t a great naturalist like his contemporaries Darwin, Alfred Russel Wallace and Henry Walter Bates. He wasn’t a great explorer (although the president of the Royal Geographical Society, Sir Roderick Murchison, wanted to believe he was), because he didn’t really penetrate that far into Central Africa, made no memorable discoveries other than the gorilla and was lousy at gathering data for maps. He wasn’t even quite the Americanized Frenchman he passed for — though to say more about that would be to give away some of Reel’s thunder. He was a gutsy opportunist with imagination and charm — and a shifting shape.

To summarize du Chaillu's significance Quammens reports from the findings of the book that

No one from the Western world, as far as we know, had laid eyes on a kangaroo until 1770. Emus, orangutans and Komodo dragons came as surprises. The earliest scientific description of a dinosaur, based on mystifying new fossils, appeared only in 1824. But the most provocative of zoological novelties was the gorilla, a Victorian sensation, for two reasons: because it was presented (falsely) as a menacing, aggressive behemoth and because it seemed, in delicious paradox, much too similar to humans for comfort. The gorilla’s very existence suggested — at just the time Charles Darwin was also suggesting — heretical ideas about the origin and nature of mankind. And the man chiefly responsible for bringing this animal to worldwide attention was Paul Du Chaillu, the central character and driving riddle of Monte Reel’s “Between Man and Beast.”

A vignette of the kind of talk du Chaillu gave is included in the biography.

[In London on] the evening of Feb. 25, 1861, at a meeting of the Royal Geographical Society, Du Chaillu lectured on his explorations to a formidable audience, including the brilliant anatomist Richard Owen, the Darwin ally Thomas Huxley, the polymath Francis Galton (who would later found eugenics) and William Gladstone. Darwin himself, a homebody with a bad stomach, didn’t attend, but his theory was in the air. On the stage beside Du Chaillu stood a pair of stuffed gorillas, “two full-grown adults,” Reel writes, “positioned in attitudes of diabolical menace.” They didn’t just command attention. They advertised an unspoken question: Do we humans share ancestry with these anthropoid monsters?

One of the things this audience was told:

Shooting a lion...is merely shooting a great beast. But there is something more dreadful in killing one of these apes. Their death is terrible, and, when in the conflict, you can but feel that if you make any mistake with the monster, he will not make any mistake with you.

This whole enjoyment of hunting has characterized mankind through it's history. This characteristic of humans seems to be dwindling. Of course hunting was necessary at one time, but that time might be drawing to a close.  Whether the drive to wipe out innocent creatures is dwindling fast enough is a different question. At least du Chaillu suggests that his own encounters were a little fairer than hunting wildlife is today.