132 



SYDNEY 



1. KLEiy. F.L.S.; F.K.A.S., OX THE 



their way into our consciousness. Tliis is more difficult to grasp 

 when the objective is near, as we are apt to confound it with 

 our sense of touch, which requires us to stretch out our hand 

 to the object, but it is clearer when we take an object far awav. 



In our telescopes we catch the rills of light which started 

 from a star a million years ago and the image is still formed on 

 the retina, althoucrh those rills are a million vears old and have 

 been falling upon mankind from the beginning of life on this 

 Globe, ready to ^^et an entrance to consciousness ; it was only 

 wheu, by evolution of thought, the knowledge of Optics had 

 evolved the telescope, that it became possible, not only to aliuw 

 that star to make itself known to us but to teach us its distance, 

 its size and conditions of existence, and even the difterent 

 Elemental substances of which it was composed a million years 

 ago ; yet, when we now allow it to form its image on the retina, 

 our consciousness insists on fixing its attention upon that star, 

 refusing to allow that it is only an image on our retina and 

 making it difficult to realize that that Star may have disappeared 

 and had no existence for the past 999.999 years, although in 

 ordinary parlance, we are looking at and .seeing it there now. 



I have referred to the sense of touch : it is. I think, clear that 

 the fii-st impiession a child can have of sight must take the form 

 of " feeling the image on its retina, as though the object were 

 actually inside the head, and it could have no idea that the 

 object was outside, until, by touching with the hand, it would 

 gradually learn by experience that the tangible object 

 coiTesponded with the image located in the head : this is borne 

 out by the testimony of men who, bom blind, had by an 

 operation receivt-d their sight late in life: their first experience 

 of seeing ,L:ave the impres.sion that the object was touching the 

 eye, and they were quite unable to recognize by sight an object 

 which they had often handled and knew perfectly well by 

 touching ; in fact, the idea of an object formed by the sense of 

 touch is so absolutely different to that formed by the sense of 

 siglit that it would be impossible without past experience to 

 conclude that the twu sen.sations referred to one and the same 

 object. The image formed on the retina has nothing in common 

 with the sense of hardness, coldness and weight experienced by 

 touch, the only impression made on the retina being that of 

 coloiu' or shades and an outliiie ; it is, however, hardly conceiv- 

 able that even the outhne of foiin would be recognized by the 

 eye, until touch had proved tliat form comprised also solidity, 

 and that the two ideas had certain motions in common both in 

 duration of time and extension in space. Again, our sense of 



