144 Transactions of the American Institute. 



tlirongli a prism, as you M-ill sec in a future lecture, the colors of tlie 

 rainbow will be produced ; the red, the yellow, and the blue. The 

 red ray corresponds to the lowest note of the gamut, the base or 

 fundamental note ; and, passing through those other colors, we reach 

 the higher notes. The undulations of sound are few. We know 

 that thirty-two to the second can be appreciated by an ordinary ear, 

 and some claim tliat they can appreciate sixteen vibrations ; from 

 this we ascend to 30,000 or 40,000 per second. But, with regard to 

 light, we pass to a degree of refinement far surpassing that of sound ; 

 for it is claimed, as the result of investigation of the undulatory 

 theory, that the red ray will perform 40,000 undulations in a single 

 inch. Light moves at the speed of 200,000 miles per second. There 

 are about 5,000 feet in a mile ; so that we have 1,000,000,000 feet, or 

 12,000,000,000 inches. Multiplying this by 40,000, we have the 

 enormous sum of 480,000,000,000,000 wavelets that break upon the 

 shore of the retina of the eye in a single second, while we gaze upon 

 a distant red star. This sum is too enormous to be appreciated. 

 Divide the little arc through which the pendulum swings in a second 

 into 1,000,000 parts ; and while the pendulum drops through one- 

 millionth part of its arc, the red waves strike upon the retina of the 

 eye 480,000,000 times. To count a million of millions requires 

 30,000 years, if we count one each second. What shall we say of 

 480,000,000,000 ? Think of the antiquity of our race, G,000 or 8,000 

 years, as compared with this astounding number ; and if we pass to 

 the higher undulations, how vastly they must exceed it. We have 

 a harmony in light, as we have a harmony in sound. When we think 

 of this, as we move off in imagination to some distant star, or to some 

 nebula, sending its light to us millions of ages ago, the mind is over- 

 Avhelraed with the thought : Truly, whatever man may be morally, 

 intellectually he is " little lower than the angels." 



