## A quotation by Johann Bernoulli

I recognize the lion by his claw.

[After reading an anonymous solution to a problem that he realized was Newton's solution.]

Quoted in G. Simmons,

*Calculus Gems*, New York: McGraw Hill, 1992, p. 136.

But just as much as it is easy to find the differential of a given quantity, so it is difficult to find the integral of a given differential. Moreover, sometimes we cannot say with certainty whether the integral of a given quantity can be found or not.

A quantity which is increased or decreased by an infinitely small quantity is neither increased nor decreased.

Quoted in D MacHale,

*Comic Sections*(Dublin 1993)