Letter from Vito Volterra, Via in Lucina 17, Rome, to Sir Joseph Larmor, Cambridge On his return to Rome, he found James Clerk Maxwell's book 'Matter and Motion', sent by Larmor and he gives thanks for this and Larmor's notes. He has found a copy of [Adolfo] Bartoli's paper on motion produced by light and heat, in the second part of which is a demonstration of the pressure of light. This was privately published, rather than in a scientific journal, and few scholars have read the original. He would be happy to send this to Larmor as a friendly token of their time together at Strasbourg. With some small pencil sketches by Joseph Larmor 22 October 1920