Sentence:  An act of parliament, empowering the plaintiffs, a company, to <WSD>ply</WSD> on Sundays from certain points on the south bank of the Thames, but imposing no obligation to provide means of transport or to maintain their plying-places, does not confer an exclusive right against the rest of the world, such as the Court of Chancery will interfere to protect; ... 
Meaning of the word marked with <WSD> tags:  To travel over (a route) regularly.