Darwin loved female company. As a boy in Shropshire, he spent time not only with his sisters and Wedgwood cousins, but with the Owen girls at Woodhouse. Later in life, Emma Darwin was entertained to see him flirting prettily, as she put it, with female visitors. He was on cordial terms with the ladies he met while he was undergoing hydropathic treatment, and Ellen Lubbock and Henrietta Huxley sent him teasing, funny letters. The formidable Lady Derby kept up an intermittent friendship with him in a series of visits and characteristically brief letters. As a old man, Darwin made an effort to reconnect with the Owen girls, sending a copy of his book on expression of the emotions to the elderly Sarah Haliburton, as she had become.

The first letter is to Darwin from an elderly friend of his family, Mary Congreve. At the time, in 1821, she would have been 75; Darwin was 12. Little is known of Mary. Her brother William, comptroller of the Royal Laboratory at Woolwich, where ammunition was manufactured, became a baronet, and his son, William, the second baronet, became famous as a rocket designer. It's tempting to suggest that the Congreve family might have fostered Darwin's youthful interest in chemistry.