528 THE POPULAR SCIENCE MONTHLY. 



the moment. The eifect of idiosyncrasy is excellently illustrated by 

 the " Number forms," where we saw that a very special sharply defined 

 track of mental vision was preferred by each individual who sees them. 

 The influence of the mood of the moment is shown in the curves that 

 characterize the various emotions, as the lank, drooping lines of grief, 

 which make the weeping-willow so fit an emblem of it. In construct- 

 ing fire-faces it seems to me that the eye in its wanderings follows a 

 favorite course, and notices the points in the pictures at large that 

 coincide with its course. It feels its way, easily diverted by associa- 

 tions based on what has just been noticed, and so, by the unconscious 

 practice of a system of " trial and error," at last finds a track that will 

 suit one that is easy to follow, and that also makes a complete picture. 

 The process is essentially the same as that of getting a clear idea from 

 out of a confused multitude of facts. The fancy picture is dwelt upon, 

 all that is incongruous with it becomes disregarded, while all deficien- 

 cies in it are supplied by the fantasy. These latest stages are easily 

 represented after the fashion of a diorama. Three lanterns are made 

 to converge on the same screen. The first throws an image of what the 

 imagination Avill discard, the second of that which it will retain, the 

 third of that which it will supply. Turn on the first and second, and 

 the picture on the screen will be identical with that which fell on the 

 retina. Shut off the first and turn on the third, and the picture will 

 be identical with the illusion. 



Visions, like dreams, are often mere patchworks built up of bits of 

 recollections. The following is one of these : 



When passing a shop in Tottenham Court Road, I went in to order a Dutch 

 cheese, and the proprietor (a bullet-headed man whom I had never seen before) 

 rolled a cheese on the marble slab of bis counter, asking me if that one would 

 do. I answered " Yes," left the shop, and thought no more of the incident. The 

 following evening, on closing my eyes, I saw a head detached from the body 

 rolling about slightly on a white surface. I recognized the face, but could not 

 remember where I had seen it, and it was only after thinking about it for some 

 time that I identified it as that of the cheesemonger who had sold me the cheese 

 on the previous day. I may mention that I have often seen the man since, and 

 that I found the vision I saw was exactly like him, although, if I had been asked 

 to describe the man before I saw the vision, I should have been unable to do so. 



Recollections need not be joined like mosaic-work ; they may be 

 blended, on the principle I described two years age, of making com- 

 posite portraits. I showed that if two lanterns were converged upon 

 the same screen, and the portrait of one person was put into one and 

 that of another person into the other, the portraits being taken under 

 similar aspects and states of light and shade, then on adjusting the two 

 images eye to eye and mouth to mouth, and so superposing them as 

 exactly as the conditions admitted, a new face will spring into exist- 

 ence. It will have a striking ai^pearance of individuality, and will bear 

 a family likeness to each of its constituents. I also showed that these 



