Of all kinds of human experience, scientific experiment is the richest: to observation it adds the control of certain factors on the strength of theoretical assumptions and, if precise, it involves measurement. Scientific experiment, when performed methodically, designed on the basis of theory, interpreted with its help and aimed at testing ideas, is said to be conducted according to the experimental method. And the experimental method is in turn often regarded as distinctive of modern factual science. A study of scientific experiment is therefore of interest to the scientist, the philosopher, and the historian of ideas.