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tlier the line be divided into successive plat-forms or levels, and ascending or descendingplanes ; or be stretched at once across thecountry without regard to any particular incli-nation : either one or other of these modes,as the case may be, will comprehend meansfor securing the regular and constant transit.
IV—STEAM-ENGINES
BY LOCO-MOTION.
The steam-engine, for many years subsequentto its discovery, was solely employed in liftingor raising water by means of pumps. Savary,Newcomen, Beighton, Desagulier, and othereminent men, successively contributed theiraid to its improvement and its advancement inutility; still it was cumbrous, heavy, unwieldy,and complicated, and its use confined withinnarrow limits. It was in this state that Mr.Watt found it, and to his enterprising geniusthe world is indebted for one of the most use-ful machines ever given to commerce and thearts. Its action was no longer confined to arectilinear motion, or that of pumping water ;but, through his assiduous exertions, convertedinto a rotatory motion, and applied to almostevery manufactory.
So early as the year 1759, steam appears tohave been thought of as a motive power towheel-carriages. In a note to the last edition