This text explores some truths behind the truism that experimentation is a hallmark of science. The intellectual and practical achievements of science have motivated a philosophical search for scientific methods of empirical access to the world, yet philosophy of science still lacks an adequate theory of observation and experiment. This is because most philosophers still construe scientists' reasoning in linguistic and formal terms which distance scientists from practical engagement with the phenomenal world and from other scientists. This text redresses the philosophical neglect of experimental practice, offering an alternative account of experiment as natural intelligence. This should be a substantial contribution to the philosophy of experiment that draws on studies of the early development of electromagnetism in the 19th century and the author's extensive knowledge of the laboratory work of one of the world's greatest experimental philosophers, Michael Faraday. Gooding uses studies of the process of real and thought experiments to show how scientists develop representations that enable thought and argument by conferring meaning upon actions, objects, instruments and procedures as well as words. He explores the roles of human agency in many kinds of experiment, going behind the orderly reconstructions of the experimental narrative to recover the process of discovery in its most exploratory form. By showing how representations emerge from pre-verbal activity in the material world this study challenges analytical philosophy's preoccupation with mental and verbal representations and its naive distinction between theory and observation. He develops the "experimenter's redress", a new form of empiricism based on the cognitive role played by the refinement of material and linguistic practice in the fine structure of experiment.