258 A. M. Mayer—History of Young's 
color.” We have here a conception of the mode of action of an 
setherial vibration on the retinal nerve fibrils which has not 
Young, as fol ; 
“For, has modern histology given us any facts concerning 
the structure of the human retina which point to the establish- 
as showing the link existing between the transmitting and sen- 
sory functions of the eye. Do not the facts of the known per- 
sistence of chemical action, after it has been once initiated, and 
the time which would be required for the retinal molecules to 
recombine, or rearrange themselves, after the etherial vibrations 
had ceased, comport with the known durations of the residual 
visual sensations, and with the main facts of physiological op- 
tics, better than the hypothesis that masses of the retinal ele- 
ments are set in vibration, rather than their molecules ?” 
It requires no argument, it is evident, that the statements 
made by Young in the foregoing paper, concerning his color 
hypothesis, were entirely hypothetical, not having been b: 
on any observation or experiment either of his own or of others. 
€ next publication by Young on his theory of color takes 
place in the following year, and is contained in the following short 
paragraph, incidentally written toward the conclusion of a 
paper read by him before the Royal Society, on July 1, 1802, 
and entitled ‘An account of some cases of the production of 
colours, not hitherto described.” 
“Tn consequence of Dr. Wollaston’s correction of the de- 
scription of the prismatic spectrum, compared with these obser- 
vations, it becomes necessary to modify the supposition that I 
advanced in the last Bakerian lecture, respecting the propor 
