Lady Mary Sheil was the first woman to publish a mention of Tahirih. It appeared in her Glimpses of Life and Manners in Persia, published in 1856, and thought to be the first such work about Persia written by woman. Read it here.
http://digital.library.upenn.edu/women/sheil/persia/persia.html
She includes accounts of the Bab and the Babi Faith and describes Tahirih and her death:
“There was still another victim. This was a young woman, the daughter of a moolla in Mazenderan, who, as well as her father, had adopted the tenets of the Bab. The Babees venerated her as a prophetess; and she was styled Khooret-ool-eyn, which Arabic words are said to mean, Pupil of the eye. After the Babee insurrection had been subdued in the above province, she was brought to Tehran and imprisoned, but was well treated. When these executions took place she was strangled. This was a cruel and useless deed.”[i]
The first book about the history of the Bab and his followers in a Western language was The Báb and the Bábis: Religious and Political Unrest in Persia in 1848-1852, written in Russian by Aleksandr Kazem-Bek, and published in 1865. Kazem-Bek was a philologist who straddled the Russian and Persian worlds; he was born in Persia, died in St. Petersburg and was of Azerbaijani origin. He wrote his first book—-on the subject of Arabic grammar—at age 17 and later converted to Christianity. (Momen)
[i] Lady Mary Sheil, Glimpses of life and manners in Persia, quoted in Farzaneh Milani, Veils and Words, The emerging voices of Iranian women writers (Syracuse, NY: Syracuse University Press, 1992), 97.