Letter from John William Gordon, Cocoa Tree [Club], St James's Street, to [William Fletcher] Barrett Discusses an experiment made by Barrett using a vibrating flame and describes his own experience of having a momentarily clear image of the rapidly spinning spokes of an omnibus wheel. He considers the cause to be a synchronised shock to the head arising from striking his heel upon the ground in walking. A second experiment of Barrett's illicits a description of a pinhole exercise to be made in a darkened room. Gordon also notes his experience of recoverable 'patches' of darkness in his vision upon awakening. 1 December 1906