Sbctiox III., 1906. [ 13 ] Tbans. R. S. C, 



II. — A Subjective Phenomenon of Vision. 

 By "W. EuPEET TxjENBrLL, M.E., Eothesay, N.B. 



(Presented by Dr. G. U. Hay.) 



1. I wish to describe in this paper a rather remarkable phenomenon 

 of vision which, as far as I can learn has never before been made public 

 (see Historical Eeview at the end of paper). 



2. The investigation has extended somewhat over a year. The 

 experiments at first were of a desultory character and it is only within 

 the latter part of the year that the subject in hand could receive due 

 attention. 



It is with some hesitation that this paper is now presented for it is in 

 many ways crude and unfinished, but the importance of the phenomenon 

 seems so great that the publication of even incomplete results seems 

 desirable. More especially as I am about entering on a most thorough 

 investigation (see supplement, written June, 1904) and hope not only to 

 profit by the criticisms of the work done and undone, but hope also that 

 this article may be the means of communicating with other persons who 

 have observed the same or a similar phenomenon. 



11. 



The Phenomenon as first, and as noiv observed. 



3. When a lad of 10 or 12 years, I saw, after retiring at night — the 

 room being dark — an image projected in space, which seemed to oscillate, 

 first in one oblique plane (1), making perhaps an angle of 30° with the 

 vertical, and then, after a confusing break in the oscillations, vibrating in 



a 



the opposite oblique plane (2) (see fig. 1. a). After oscillating in the 

 second oblique plane for perhaps a few seconds the image lost what defin- 

 iteness of contour it had and apparently broke up into bright points re- 

 sembling myriads of stars. These points seemed to stream before the 



