OCULAR SPECTRA. 109 



see anything which is difficult to be seen, I could make 

 the phantasm return without looking any more upon the 

 sun ; and the oftener I made it return, the more easily I 

 could make it return again. And at length, by repeating 

 this without looking any more upon the sun, I made such 

 an impression on my eye, that, if I looked upon the 

 clouds, or a book, or any bright object, I saw upon it a 

 round bright spot of light like the sun, and, which is still 

 stranger, though I looked upon the sun with my right 

 eye only, and not with my left, yet my fancy began to 

 make an impression upon my left eye as well as upon my 

 right. For if I shut my right eye, and looked upon a 

 book or the clouds with my left eye, I could see the 

 spectrum of the sun almost as plain as with my right eye, 

 if I did but intend my fancy a little while upon it ; for at 

 first, if I shut my right eye, and looked with my left, the 

 spectrum of the sun did not appear till I intended my 

 fancy upon it ; but by repeating, this appeared every time 

 more easily. And now in a few hours' time I had brought 

 my eyes to such a pass, that I could look upon no bright 

 object with either eye but I saw the sun before me, so 

 that I durst neither write nor read ; but to recover the 

 use of my eyes, shut myself up in my chamber made 

 dark, for three days together, and used all means in my 

 power to direct my imagination from the sun. For if I 

 thought upon him, I presently saw his picture, though I 

 was in the dark. But by keeping in the dark, and em- 

 ploying my mind about other things, I began in three or 

 four days to have more use of my eyes again ; and by 

 forbearing to look upon bright objects, recovered them 

 pretty well ; though not so well but that, for some months 

 after, the spectrums of the sun began to return as often 

 as I began to meditate upon the phenomena, even though 

 I lay in bed at midnight with my curtains drawn. But 

 now I have been very well for many years, though I am 



