Home > Francesco Maria Grimaldi

Between 1640 and 1650, working with Riccioli, he investigated the free fall of objects, discovering that the distance of fall was proportional to the square of the time taken.

In astronomy, he built and used instruments to measure geological features on the Moon, and drew an accurate map or selenograph which was published by Riccioli.

He was the first to make accurate observations on the diffraction of light (although Leonardo Da Vinci had earlier noted it), and coined the word 'diffraction'. Later physicists used his work as evidence that light was a wave, and Isaac Newton used it to arrive at his more comprehensive theory of light.

Publications

• Physicomathesis de lumine, coloribus, et iride, aliisque annexis (published 1665Events March 4 Start of the Second Anglo-Dutch War March 6 Philosophical Transactions of the Royal Society begins publication March 16 Bucharest allows Jews to settle in the city in exchange of annual tax of 16 guilders June 3 The Duke of York defeats the)