The most outstanding Rajput ruler of the 18th century was Raja Sawai Jai Singh of Amber. He was a distinguished statesman lawmaker and reformer. But most of all he shone as a man of science in an age when Indians were oblivious of scientific progress. He founded the city of Jaipur and made it a great seat a science and art. Jaipur was built upon strictly scientific principles and according to a regular plan. Its broad streets are intersected at right angles.
Jai Singh was above everything a great astronomer. He erected observatories with accurate and advanced instruments some of them of his own invention, at Delhi (Jantar Mantar) Jaipur, Ujjain Varanasi and Mathura. His astronomical observations were remarkably accurate. He drew up a set of tables entitled Zij Muhammedshahi to enable people to make astronomical observations. He had Euclid’s ‘Elements of Geometry’ translated into Sanskrit as also several works on trignometry and Napier’s work on the construction and use of logarithms.
Jai Singh was also social reformer. He tried to enforce a law to reduce the lavish expenditure which the Rajputs had to incur on their daughter’s weddings. This had given rise to the evil practice of infanticide. This remarkable prince ruled Jaipur for nearly 44 years from 1699 to 1743.