Lives of Boulton and Watt. Principally from the Original Soho MssNote 147 — Chapter XII · Boulton and Watt begin the Manufacture of Steam-engines.Reading editionWatt to Boulton, 3rd July, 1776. Boulton MSS.◇Copy noteReturn to CHAPTER XII. Boulton and Watt begin the Manufacture of Steam-engines.