Text 4 Clouds are notoriously unruly.Make It Rain,Kristine Harper"s detailed history of weather control in the United States,reminds us that clouds have been objects of desire and frustration for some time.Her story of the messy interface between science and govemment policy unfolds across the 20th century,but it reaches its emotional crest in the 1950s.Although she includes colorful details of cloud-seeding experiments,Harper"s story is not so much about attempts to control the weather as it is about the political battles waged over the control of the atmosphere.But Harper"s focus on govemment policy is what makes this study so worthwhile.Scientific facts,she demonstrates,were never central to weather control policies.When meteorologists were consulted,they usually replied that our basic physical understanding still fell far short of what was required to intervene in the weather in responsible or effective ways.More research,they argued,was needed before action could be taken.Officials in the Departments oflnterior and Defense looked elsewhere for scientific support.They found a few key figures willing to play the role of experts,including the mathematician and computer architect John von Neumann and Irving Langmuir,a Nobel laureate chemist employed by General Electric（G E）.Langmuir,who used supercooled GE freezers to simulate clouds,assumed that what worked in the laboratory would work in the atmosphere itself.After inconclusive field experiments in New Mexico,he made plausible reports that just a few pounds of dry ice or silver iodide could generate precipitation over thousands of square mrles.The truth was more complex and the prospects for actual control much less favorable.It was sometimes possible to coax water out of clouds that already existed.It was not possible to generate water-and clouds-where none existed.Yet such details,and the physical facts behind them,did remarkably little damage to govemment plans for hamessing the awesome power of the atmosphere.Rather than revealing a history of what we might today call evidence-led policy,here is a rogue"s gallery of policy~led evidence.Drawing on the work of Brian Balogh,Harper calls such programs the workings of a"proministrative state,"in which a governing body sells the people services that the people have not.in fact,demanded.After a series of relatively benign（and frequently unsuccessful）domestic projects during the 1950s,the United States started its weather control efforts on the world stage.Some interventions were peaccful,such as an attempt to mitigate drought in the Bihar region oflndia in 1967.Others were not.36.Kristine Harper"s study is valuable because