Which of Harriet Martineau's books is a foundational treatise on sociological data collection?

Harriet Martineau's book that serves as a foundational treatise on sociological data collection is "How to Observe Morals and Manners (1838)." In this book she articulates the principles and methods of empirical social research. The book also provides a positivist solution to the correspondence problem between inter-subjectivity, verifiable observables, and un-observable theoretical problems.