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In 1854 , he built an experimental rotary steam engine , which when installed in a 300-ton screw-propelled ship , reportedly achieved an rpm of 45 and a top speed of 14 mph in tests conducted by the firm of Boulton & Watt .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
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