C34 Professor Jagadis Chunder Bose [May 10, 



with a water lens, which, in its liquid constitution, approximates 

 closer to the lens of the eye than does the glass substitute. In this 

 case the, to us invisible, radiations are absorbed by the liquid, and 

 do not reach the sensitive retina. Perhaps we do not sufficiently 

 appreciate, especially in these days of space-signalling by Hertzian 

 waves, the importance of that protective contrivance which veils our 

 6ense against insufferable radiance. 



Fig. 14. — (a) Kesponse curves of artificial retina for short periods of illumina- 

 tion followed by darkness. The ascending portions show the growing effect of 

 light, the horizontal portion the balancing tetanic effect. The descending portion 

 of the curve exhibits recovery during the absence of light, (b) Same in frog's 

 retina (Waller). 



I give here two sets of curves, one exhibiting the response of the 

 artificial retina and the other of that of a frog, to show the general 

 resemblance of the two (Fig. 14). 



I have referred to the fact that sometimes on the 

 Binocular cessation of light, an after-oscillation is observed, 



Alternation which may correspond to the after-oscillations of 

 of Vision* the retina, and give a probable explanation of the 

 phenomena of recurrent vision. When we have 

 looked at a bright object for some time with one eye, we find, on 

 closing both eyes, that the image of this object alternately appears 

 and disappears. It was while studying this subject that I came upon 

 the curious fact that the two eyes do not see equally well at a given 

 instant, but take up, as it were, the work of seeing, and then (relatively 

 speaking) resting, alternately. There is thus a relative retardation of 

 half a period as regards maximum sensation in the two retinas. This 

 may be seen, by means of a stereoscope, carrying, instead of stereo- 

 photographs, incised plates through which we look at light. The 

 design consists of two slanting cuts at a suitable distance from each 

 other. One cut, E, slants to the right, and the other, L, to the left 

 (see Fig. 15). When the design is looked at through the stereo- 

 scope, the right eye will see, say K, and the left L ; the two images 



See Electrician, Sept. 1900. 



