Letter from A [Alfred] Senier, Gurthard House, Galway, to [Joseph] Larmor, Cambridge Since he last wrote about the light-sensitive compound, they have subjected it to rigid tests and have searched past work records. Tests confirmed the property as first described, which is due to rays of light of high refrangibility. Although the phenomenon is new to them, records show it is known 'across the Rhine' and [Willy] Marekwald names the property 'phototropy'. Senier has sent a report on the compound to the Chemical Society, giving the title 'Salicylidene...'. They propose to continue the work and since the paper was sent they have found more phototropic compounds. He though it would interest Larmor, and he will know if this bears upon the problems of light. 14 February 1909