Diagrams, optics experiments and observations by J T [John Theophilus] Desaguliers 13 diagrams, labelled figures 1-13, showing observations from experiments made using prisms. Subject: Optics Read to the Royal Society in July 1714 Published in Philosophical Transactions as 'An account of some experiments of light and colours, formerly made by Sir Isaac Newton, and mention'd in his opticks, lately repeated before the Royal Society, by J. T. Desaguliers, F. R. S' 1714