THE EYES OF SCIENCE. 



301 



take, for instance, one of Dr. Rutherford's photographs 

 of the solar disc, and compare the spots there depicted 

 with those shown even in the most carefully executed 

 pictures of the sun before and since, we see at once 

 how liable the eye is either to be deceived in what it 

 sees, or else to fail duly to guide the hand in repro- 

 "" ducing what the eye has seen. I happen to know of a 

 case where a draughtsman took exceptional pains to 

 reproduce, without exaggeration, the aspect of the 

 solar disc with its spots, yet, on comparison being 

 made with a photograph taken nearly at the same 

 time (though 3,000 miles away), it appeared that the 

 spots had been notably exaggerated. I refer to the 

 drawing of the sun's face which forms the frontispiece 

 of my treatise on The Sun. I was particularly struck 

 by the aspect of the sun when that drawing was made, 

 and I certainly spared no pains to delineate the spots 

 correctly ; but a comparison of my picture with a well- 

 known photograph by Rutherford, which chanced to 

 be taken about the same time in New York, will show 

 that though the spots are delineated, individually, 

 correctly enough, they are considerably too large as 

 compared with the solar disc an enlargement by no 

 means necessary to enhance their importance, for the 

 largest spot visible on that occasion had a surface 

 several times larger than the entire surface of this 

 earth. 



Other instances of .the same sort may readily be 

 cited. A very noteworthy case, in which the imper- 

 fection of ordinary vision and ordinary methods of 



