VOL. LXXXVI.] 



PHILOSOPHICAL TRANSACTIONS. 



725 



Compound Characters, expressing the wavering of Star-light. 



'. From the least perceptible difference less bright to equality. 

 ; From equality to the least perceptible difference more bright. 

 ■7 From a very small difference more bright, to the least perceptible difference. 

 =, From — , to — &:c. 



I The wavering expressed by the passing of the light from a state of the least perceptible difference 

 less bright to equality, and to the least perceptible difference more bright. 



~ The vi^avering expressed by the changes from — to , and to , or from . to , and to — . 



General Characters. 



= Perfect equality. 



< Less, but undetermined. 



> Larger, but undetermined. 



A specimen of the catalogue, to show the manner, is as follows. 

 1. Catalogue of the comparative Brightness of (he Stars. 



X. Experiments aiid Observations on the Inflection, Reflection, and Colours of 

 Light. By Henry Brougham, Jan., Esq. p. 227. 



It has always appeared wonderful to me, since nature seems to delight in 

 those close analogies which enable her to preserve simplicity and even uniformity 

 in variety, that there should be no dispositions in the parts of light, with 

 respect to inflection and reflection, analogous or similar to their different 

 refrangibility. In order to ascertain the existence of such properties, I 

 began a course of experiments and observations, a short account of which forms 

 the substance of this paper. For the sake of perspicuity I shall begin with the 

 analytical branch of the subject, comprehending my observations under 

 1 parts; flexion, or the bending of the rays in their passage by bodies, 

 and reflection. And I shall conclude by applying the principles there esta- 

 blished to the explanation of phenomena, in the way of synthesis. 



Part 1. Of Flexion. — In order to fix our ideas on a subject which has never 

 been treated of with mathematical precision, we shall suppose, for the present, 



