As the years passed, the sprawling house at Down filled up with children—the Darwins would have ten in all—and a series of governesses, nurses and pets. Charles and his wife Emma were relaxed and affectionate parents whose children, daughter Henrietta later wrote, felt like "creatures whose opinions and thoughts were important."

Since London days Darwin's health had been fragile. Breaks in the regular routine—even an interesting talk with a visitor—could provoke spells of vomiting and dizziness. But he doggedly pursued his research program, and on some days his work could be an exciting household adventure. Children tracked the flight paths of bumblebees, a governess joined in counting the plant species in a meadow, a longtime servant helped Darwin boil carcasses of small mice and birds to "skeletonise" them for study.

Yet Down House was full of ordinary life as well. Family friend Joseph Hooker recalled "long walks, romps with the children on hands and knees, and music that haunts me still."

FATHER AND SON

Above is the only known daguerreotype of Darwin with a family member. Done in 1842, it shows Darwin with his first son, William. In the mid-1800s boys often wore dresses until the age of four or five.