it,) and found that each fihre was distinctly visible, brilliantly 

 illuminated. 



On substituting the prepared cotton, he found that no 

 illumination of the fibres took place, all were dark and almost 

 invisible, one only here and there being seen of a purplish 

 hue ; when the cotton had been badly prepared, a great 

 number of the fibres were illuminated. The experiment was 

 much more striking, when Tow was used instead of Cotton. 

 The contrast between the dull fibres of the explosive, and the 

 beautiful irridescent appearance of the common, being very 

 complete. 



Dr. Brett gave an account of some experiments made 

 some years ago, with a view of producing fulminating com- 

 pounds, by the same means by which the Gun Cotton was now 

 produced. 



The President then delivered the following 

 ADDRESS. 



" Gentlemen. — It is, I believe, the custom in this Society, 

 as in others similarly constituted, that the President should, 

 on his election, address to you a few observations, not only 

 as expressive of his thanks for the honour conferred upon 

 him, but as also indicating his sentiments on the present 

 aspect of literature and science, more especially as regards 

 the Society over which he has the honour to preside. Con 

 trolled by so many precedents, I should not be justified in 

 deviating from this custom, thus established by usage and 

 manifest propriety, but will make a few remarks before I 

 proceed to the subject appointed for this evening — a subject 

 highly abstract and exceedingly obscure, ranging, as it 

 does, among the metaphysics of mathematics. I may be 

 very naturally asked, Why bring before the Society such 

 abstruse conceptions and subtle speculations ? It is, because 

 I am of opinion that we should propose to ourselves, whether 

 we attain to it or not, a high standard of excellence ; that we 

 should endeavour to elevate the character of our proceedings, 



