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152 advanc'd with mighty Steps in his Geometry, and was arriv'd at the very Borders of Infinity; but went no farther. Dr. Wallis about the Middle of the lat Century, was the firt who reduc'd a Fraction by a perpetual Diviion to an infinite Series. Lord Brounker employ'd this Series to quare the Hyperbola. publih'd a Demontration of this Quadrature, much about which Time, Sir Iaac Newton being then twenty three Years of Age, had invented a general Method to perform, on all geometrical Curves, what had jut before been try'd on the Hyperbola. to this Method of ubjecting every where Infinity to algebraical Calculations, that the Name is given of differential Calculations or of Fluxions, and integral Calculation. 'Tis the Art of numbring and meauring exactly a Thing whoe Exitence cannot be conceiv'd., indeed, would you not imagine that a Man laugh'd at you, who hould declare that there are Lines infinitely great