That the duty performed by Messrs. Boulton and Watt's improved steam-engines in 1798 (as appears by a statement made by Davies Gilbert, Esq, and other gentlemen, associated for that purpose) averaged only 14?? millions pounds of water lifted one foot high by one bushel of coals, although a chosen engine of theirs, at Herland, under the most favourable circumstances, lifted 27 millions???the great