Watt’s house, Harper’s Hill--First order for engines--Boulton’s activity--The London engineers prophesy the failure of Watt’s engine--Watt revisits Glasgow--His second marriage--Terms of partnership between Boulton and Watt--Orders from Scotland for engines--Boulton pressed with work and anxiety--Watt returns to Soho with his wife--Order for engine for Tingtang and Chacewater mines, Cornwall--Watt and the Shadwell Waterworks Committee--Stratford-le-Bow engine--Difficulties with workmen at Soho, and with unskilled enginemen--Expansive working 214–229 CHAPTER XIII. Inefficiency of the Newcomen pumping-engines--More orders from Cornwall--Watt in Cornwall--United Mines district--Mines drowned--Watt and Jonathan Hornblower--Mrs. Watt’s account of Cornwall--Chacewater engine finished--Its successful working--Watt’s embarrassments and financial difficulties--Boulton’s courage and perseverance, and Fothergill’s despondency--Fire at Soho--Engine royalty on savings of fuel--Altercations with adventurers--Watt’s frequent calls for Boulton’s help--Boulton’s harassments--Proceeds to Cornwall--Watt’s return to Birmingham--His despondency--Boulton sustains the firm--Orders for engines from abroad--William Murdock, his excellencies of character and ability--First interview with Boulton and engagement--Sent to Cornwall--His mode of dealing with the captains--Watt’s altercations with the Cornishmen--His reliance on Boulton--Altercation with Trevithick 230–260 CHAPTER XIV. Lieutenant Henderson in Cornwall--Boulton’s financial embarrassments increase--Boulton and Fothergill--The “Soho pictures”--Watt’s letter-copying machine--Boulton pushes the machine--Demand for copying-presses--More financial difficulties--Watt’s sufferings and melancholy--More Cornish engines wanted--Engine-dues--Boulton cheers Watt--Mining adventurers’ meetings--Boulton and Watt take shares--The mines--Boulton organises the mining business--Boulton’s house at Cosgarne, Cornwall--Mrs. Watt describes her husband’s miseries and weakness--The engine patent threatened by the Cornish men--Watt on patent right--The Birmingham Copper Company--Boulton improves engine-boilers by introducing tubes--His MSS. and drawings concerning mechanical and scientific experiments--His indefatigable industry 261–284 CHAPTER XV.