474 



Mr. H. F. Newail. 



[Jan. 25, 



6. Both methods lead, as I have said, to practically the same 

 results. The ghost then is independent of the position of the eye-ball 

 in the socket, and hence must he produced by reflexions internal to 

 the eye, and not brought about by its external surroundings. 



7. Nearer inspection of the ghost itself showed it to be an inverted 

 image of the candle, about equal in size, very faint, and of a slightly 

 dull bluish tint. 



8. Before saying more I will describe what has proved the easiest 

 way of finding the ghost. Stand opposite a uniformly dark wall in a 

 darkened room. Direct the eyes to any point in front (e.g., a mark 

 on the wall, a pin in a curtain) , and keeping the eyes fixed and being 

 ready to perceive any appearance out of the line of direct vision 

 without moving the eyes towards it, hold up a candle at arm's length, 

 and move it to and fro over about two inches, on a level with the 

 point fixed, and a little to the right or the left of it. The ghost (or 

 rather ghosts, if both eyes are used) may be seen moving with a 

 motion opposite to that of the candle on the other side of the point of 

 direct vision. 



9. The best way that I have found for observing the image, is to 

 set a candle on the table about a foot from the eye, and place close in 

 front of it a dark-coloured board two or more feet in length, and of 

 breadth just enough to allow the flame of the candle to be seen above 

 when the board is set up breadthwise on its edge. Now let the eye be 

 fixed on any object which can be moved along the top edge of the 

 board. When this point moves the eye follows it with a regular steady 

 motion, which I have failed to get by any other method, such as the 

 seemingly more simple one of letting the gaze move along the edge of 

 the board, unhelped by a moving point. The board in shadow makes 

 the best background for faint images, such as the "ghost," which will 

 be found in the position above described. 



10. In either of the methods described in the two last paragraphs, 

 the motion of the candle or of the moving point should be slow, and 

 to and fro, over a short range:; but it should be continued till the 

 image is found, for if the image rests, it makes less and less impression 

 on the retina, 



11. Since the ghost depends on the state of the accommodation of 

 the eye, for distinctness and even visibility (see below, §§ 15-20), it 

 follows that people with different sight may have to look for the ghost 

 in different ways. A short-sighted person for instance, will probably 

 not be able to see it in the middle of the field at all, and so may fail to 

 recognise the phenomenon, unless indeed his short sight is due to too 

 great convexity of the cornea only. 



12. Beyond a mere cursory investigation of the phenomenon, I did 

 nothing at the subject at the time ; but later, having need to consult 

 Mr. R. Liebreich, I asked him if he knew of the phenomenon. He 



