404 



The same explanation that I ventured to offer in the Bakerian 

 Lecture for 1858, as to the cause of the stratified discharge arising 

 from the impulses of a force acting on highly attenuated but resist- 

 ing media, is also applicable to the discharge of the voltaic battery 

 in vacua ; while the fact of this discharge, even its full intensity 

 having been now ascertained to be also stratified, leads me to the 

 conclusion, that the ordinary discharge of the voltaic battery, under 

 every condition, is not continuous, but intermittent ; that it consists 

 of a series of pulsations or vibrations of greater or lesser velocity, 

 according to the resistance in the chemical or metallic elements of 

 the battery, or the conducting media through which the discharge 

 passes. 



March 22, 1860. 

 Sir BENJAMIN C. BRODIE, Bart., President, in the Chair. 



In accordance with the notice given at the last meeting, the Right 

 Honourable Edward, Lord Belper, was proposed for immediate 

 ballot ; and the ballot having been taken, his Lordship was declared 

 duly elected. 



The following communications were read : 



I. "On the Theory of Compound Colours, and the Relations of 

 the Colours of the Spectrum/' By J. CLERK MAXWELL, 

 Esq., Professor of Natural Philosophy, Marischal College 

 and University, Aberdeen. Communicated by Professor 

 STOKES, Sec. R.S. Received December 27, 1859. 



(Abstract.) 



Newton (in his * Optics,' Book I. part ii. prop. 6) has indicated a 

 method of exhibiting the relations of colour, and of calculating the 

 effects of any mixture of colours. He conceives the colours of the 

 spectrum arranged in the circumference of a circle, and the circle so 

 painted that every radius exhibits a gradation of colour, from some 

 pure colour of the spectrum at the circumference, to neutral tint at 

 the centre. The resultant of any mixture of colours is then found 



