In a 1976 paper, Robert DeKosky wrote ‘William Crookes is a puzzle to historians of latenineteenth century science. Despite his achievements we are forced to ask why he did not accomplish more.’ It is an interesting question; equally interesting is the question that prompts this paper – how did he accomplish so much?Why some scientists become prolific and successful is a question with both historical and ahistorical dimensions. Among the former are a number of cultural aspects rarely studied by historians. (...) They include the nature of childhood experience, family attitudes, mentoring, and the existence of intellectual and practical support networks in adulthood. Ail are important, but how they contribute to individual success varies with time and place. (shrink)

This essay examines the technical evolution and scientific context of William Crookes's effort to achieve an absolute vacuum in the 1870s. Prior to late 1876, along with interrogation of the radiometer effect, the quest for perfect vacuum was a major motive of his research programme. At this time, no absolutely dependable method existed to determine exactly the pressures at extreme rarefactions. Crookes therefore employed changes in radiometric, viscous and electrical effects with changing pressure in order to monitor the progress of (...) exhaustion. After late 1876, his research priorities shifted because he had reached a plateau of technical accomplishment in the effort to attain extreme vacua, and because observed effects in vacua—particularly electrical—assumed an importance in their own right, and as bases for elucidation and defence of his concept of a ‘fourth state of matter’ at very low pressures. (shrink)