When the mill was at length set to work, it performed to the entire satisfaction of its projectors. The engine, on one occasion, ground as much as 3000 bushels of wheat in twenty-four hours. The usual rate of work per week of six days was 16,000 bushels of wheat, cleaned, ground, and dressed into fine flour (some of it being ground two or three times over); or sufficient, according to Boulton’s estimate, for the weekly consumption of 150,000 people. The important uses of the double rotative engine were thus exhibited in the most striking manner; and the fame of the Albion Mill extended far and wide. It so far answered the main purpose which Boulton and Watt had in view in originally embarking in the enterprise; but it must be added that the success was accomplished at a very serious sacrifice. The mill never succeeded commercially. It was too costly in its construction and its management, and though it did an immense business it was at a loss. The concern was, doubtless, capable of great improvement, and, had time been allowed, it would probably have come round. When its prospects seemed to be brightening,[281] it was set on fire in several places by incendiaries on the night of the 3rd of March, 1791. The villains had made their arrangements with deliberation and skill. They fastened the main cock of the water-cistern, and chose the hour of low tide for firing the building, so that water could not be got to play upon the flames, and the mill was burnt to the ground in a few hours. A reward was offered for the apprehension of the criminals, but they were never discovered. The loss sustained by the Company was about 10,000_l._ Boulton and Watt were the principal sufferers; the former holding 6000_l._, and the latter 3000_l._ interest in the undertaking.[282] [281] Watt wrote Boulton from London, 1st October, 1789,--“I called on Wyatt (the architect) last night. He says the mill sold above 4000_l._ worth of flour last week and is doing well.” [282] For further particulars as to the Albion Mill, see Life of Rennie in ‘Lives of the Engineers,’ ii. 137.