The labyrinth and abyss of infinity is also a new course Sir Isaac Newton has gone through,and we are obliged to him for the clue,by whose assistance we are enabled to trace its various windings.
Descartes got the start of him also in this astonishing invention.
He advanced with mighty steps in his geometry,and was arrived at the very borders of infinity,but went no farther.Dr.Wallis,about the middle of the last century,was the first who reduced a fraction by a perpetual division to an infinite series.
The Lord Brouncker employed this series to square the hyperbola.
Mercator published a demonstration of this quadrature;much about which time Sir Isaac Newton,being then twenty-three years of age,had invented a general method,to perform on all geometrical curves what had just before been tried on the hyperbola.
It is to this method of subjecting everywhere infinity to algebraical calculations,that the name is given of differential calculations or of fluxions and integral calculation.It is the art of numbering and measuring exactly a thing whose existence cannot be conceived.
And,indeed,would you not imagine that a man laughed at you who should declare that there are lines infinitely great which form an angle infinitely little?
That a right line,which is a right line so long as it is finite,by changing infinitely little its direction,becomes an infinite curve;and that a curve may become infinitely less than another curve?
That there are infinite squares,infinite cubes,and infinites of infinites,all greater than one another,and the last but one of which is nothing in comparison of the last?
All these things,which at first appear to be the utmost excess of frenzy,are in reality an effort of the subtlety and extent of the human mind,and the art of finding truths which till then had been unknown.
This so bold edifice is even founded on simple ideas.The business is to measure the diagonal of a square,to give the area of a curve,to find the square root of a number,which has none in common arithmetic.After all,the imagination ought not to be startled any more at so many orders of infinites than at the so well-known proposition,viz.,that curve lines may always be made to pass between a circle and a tangent;or at that other,namely,that matter is divisible in infinitum.These two truths have been demonstrated many years,and are no less incomprehensible than the things we have been speaking of.
For many years the invention of this famous calculation was denied to Sir Isaac Newton.In Germany Mr.Leibnitz was considered as the inventor of the differences or moments,called fluxions,and Mr.
Bernouilli claimed the integral calculus.However,Sir Isaac is now thought to have first made the discovery,and the other two have the glory of having once made the world doubt whether it was to be ascribed to him or them.Thus some contested with Dr.Harvey the invention of the circulation of the blood,as others disputed with Mr.Perrault that of the circulation of the sap.
Hartsocher and Leuwenhoek disputed with each other the honour of having first seen the vermiculi of which mankind are formed.This Hartsocher also contested with Huygens the invention of a new method of calculating the distance of a fixed star.It is not yet known to what philosopher we owe the invention of the cycloid.
Be this as it will,it is by the help of this geometry of infinites that Sir Isaac Newton attained to the most sublime discoveries.Iam now to speak of another work,which,though more adapted to the capacity of the human mind,does nevertheless display some marks of that creative genius with which Sir Isaac Newton was informed in all his researches.The work I mean is a chronology of a new kind,for what province soever he undertook he was sure to change the ideas and opinions received by the rest of men.
Accustomed to unravel and disentangle chaos,he was resolved to convey at least some light into that of the fables of antiquity which are blended and confounded with history,and fix an uncertain chronology.It is true that there is no family,city,or nation,but endeavours to remove its original as far backward as possible.
Besides,the first historians were the most negligent in setting down the eras:books were infinitely less common than they are at this time,and,consequently,authors being not so obnoxious to censure,they therefore imposed upon the world with greater impunity;and,as it is evident that these have related a great number of fictitious particulars,it is probable enough that they also gave us several false eras.
It appeared in general to Sir Isaac that the world was five hundred years younger than chronologers declare it to be.He grounds his opinion on the ordinary course of Nature,and on the observations which astronomers have made.
By the course of Nature we here understand the time that every generation of men lives upon the earth.The Egyptians first employed this vague and uncertain method of calculating when they began to write the beginning of their history.These computed three hundred and forty-one generations from Menes to Sethon;and,having no fixed era,they supposed three generations to consist of a hundred years.In this manner they computed eleven thousand three hundred and forty years from Menes's reign to that of Sethon.
The Greeks before they counted by Olympiads followed the method of the Egyptians,and even gave a little more extent to generations,making each to consist of forty years.
