352 Mr, G. Docld on 



included in the former class, and all which, are separated 

 at the copper surface in the latter class. 



If we refer to the figure, and suppose the atoms of oxygen 

 to be plates of zinc, and the atoms of hydrogen plates of 

 copper, and that the former are united to the latter in the 

 usual manner, so as to form a galvanic series of three alter- 

 nations of the metals ; it is evident, that the zinc will pre- 

 sent a negative, and the copper a positive surface in the 

 cells between the plates B and C, and between D and E ; 

 and also, that when a conducting communication is made 

 between A and F, the light will flow from the negative 

 surface of the zinc plate A, to the positive surface of the 

 copper plate F. It therefore appears, that although zinc 

 is positive and copper negative, when water is decomposed 

 by the galvanic action of these metals, its oxygen is evolved 

 at a negative, and its hydrogen at a positive surface. 



This arrangement derives considerable support, from its 

 agreement with the refractive force of the different bodies 

 which are thus placed in the positive and negative classes ; 

 the former being known to repel, and the latter to attract the 

 light, when it falls obliquely upon their several surfaces. 



It may be supposed that the subjects of this paper are 

 not sufficiently prominent to become distinct objects of 

 investigation ; but it is by attention to minute particulars 

 that we arrive at general conclusions ; and to prove the 

 soundness of such conclusions, we are frequently called 

 upon to retrace our steps, by producing particular cases to 

 which they are applicable ; the magnitude of the subjects, 

 under these circumstances, is not measured by our usual 

 views of their importance, so much as by the ease and 

 simplicity with which the theory applies to their explana- 

 tion, and the opportunities they offer for its general illus- 

 tration. P. Cooper. 



Weston Super Mare, Oct. 6, 1836. 



To the Editor of the Records of General Science. 



Article VII. 

 On Internal Prismatic Reflexion, By Mr. George Dodd. 



{To the Editor of the Records of General Science.) 

 Sir, — The ingenious and interesting papers of your corre- 

 spondent, Mr. Cooper, on the nature of white light, contain 



