What are the specific contributions of Harriet Martineau?

Answer 1

In what area? You're asking a seriously broad question. She influenced feminism, poetry, politics, philosophy, journalism, etc etc. The best thing to do would be to look her up and read about life works in order to find the specific things you are looking for. Here are two good places to start:
http://en.wikipedia.org/wiki/Harriet_Martineau
http://www.britannica.com/eb/article-9051172/Harriet-Martineau

Answer 2

The highlights of Martineau's many-faceted life and remarkable work are organized into nine subsections, beginning with her life "as a girl-child". Her story is then discussed under the following subtitles: "as an early feminist", "as a philosopher", "as an educator", as a novelist and writer of children's stories", "as a social reformer", "as a pioneering social scientist", "as a journalist" and, finally, "as a victim of institutionalized sexism