Letter from J H [John Henry] Poynting, 10 Ampton Road, Edgbaston, Birmingham, to [Joseph] Larmor Poynting is setting up the prism experiment and will try what Larmor suggested. He questions if Larmor is right, supposing the beam is a stream of momentum, where a reflection may neutralise the other at some angle. They are more sure of momentum than electromegnetic theory, the latter to adjust itself to the former. Poynting has been having difficulties with gas actions within a pressure experiment. His first apparatus was well constructed but the effect is different in the reconstruction. 25 May 1905