He greatly enriched the cajculus and was very influential in making the power of the new subject apprecianted in contincntal Europe. Nicolaus, who showed great promise in the field of mathematics, was called to the St. Petersburg Academy, where he unfortunately died by drowining, only eight months later. He wrote on curves, differential equations, and probability. A problem in probability, which he proposed from St. Peresburg, later became known as the Petersburg paradox.
Mathematical theory shows that A 's expectation is infinite, which seems a paradoxical result.
The problem was incestigated by Nicolaus' brother Daniel, who succeeded Nicolaus at St. Petersburg. Daniel returned to Basel seven years later. He was the most famous of Johann's three sons, and devoted most of his energies to probability, astronmy, physics and hydrodynamics. In probability he debised the concept of moral expectation , and in his Hydrodynamica , of 1738, appears the principle of hydrodynamics that bears his name in all present-day elementary physics texts. Johann II, the youngest of the three sons, studied law but spent his later years as a professor of mathematics at the University of Basel.