One of the his more noted pieces of work is his contribution to the problem of the brachyshochrone the determination of the curve of quickest descent of a weighted particle moving between two given points in a gravitation field; the curve turned out to be an arc of an appropriate cycloid curve. This problem was also discussed by Jakob Bernoulli.The cycloid curve is also the solution to the problem of the lautochrone – the determination of the curve along which a weighted particle will arrive at a given poin of the curve in the same time interval, which was more generally discussed by Johann Bernoulli, Eurrer, and Lagrange, had earlier been solved by Huygens (1673) and Newton (1687), and applied by Huygens in the construction of pendulum clocks (see Problem Study 10.9(c)).