Letter from C G [Charles Glover] Barkla, Physical Laboratory, the University, Edinburgh, to [Joseph] Larmor Barkla was shocked to see how long he had left Larmor's note unanswered, but he cannot answer satisfactorily, or with a conclusion. He was interested in Larmor's views on the processes of absorption radiation. Barkla likes the idea that a quatised atom is sufficient without the assumption of light-quanta. He discusses the difficlties raised by the C.T.R. Wilson and Auger condensation experiments. He thinks that a spreading wave theory cannot be superseded, only supplemented. An atom in absorbing condition might 'mop up radiation from all sides, and from considerable distances'. Experiments of the next few years will settle the matter. He has been thinking mostly about his own experiments and what a vast region there is to be explored. A slight change in what has been accustomed to be regarded as an unimportant detail completely alters the absorption experiment results 'as though a switch were turned by an invisible hand'. 27 June 1927