62 Imperial Institute of France. 



ported by the secretary : among them were the following, 

 which have now for the first lime been noticed in the re- 

 spective places : ** Arsenical pyrites in quartz, found by 

 Dr. Ogilby at Hoath, county Dublin — Gray ore of man- 

 ganese with white lead ore from the Scalp, county Wick- 

 low — Specular iron ore found by Dr. Ogilby in rocks of 

 tlie trap formation, county Antrim." 



A paper " On Light" was read by Cornelius Keogh^ 

 esq. proposing to the Society the trial of certain experi- 

 ments intended to confirm the analogy between light and 

 sound. 



Andrew Carmicbael, esq. read part of a paper of con- 

 siderable length, in which he adduced many reasons ia 

 support of a new hypothesis of the nature of electricity, 

 viz. That the sun is the source of that principle, as well as 

 of light and heat ; and that the deoxygenating ray is the 

 base of the two electric fluids. — The facts he has collected 

 tend to demonstrate, that, in combination with the colorific 

 ray, it forms positive electricity ; and, in combination with 

 the calorific ray, negative electricity. — A more copious abs- 

 tract of the theory will be given, after Mr. Carmichael has 

 read the remainder of his paper. 



IMPERIAL INSTITUTE OF FRANCE. 



[Continued from vol. xl. p. 468.] 



It does not become us to hazard an opinion, when 

 botanists so eminent are at issue ; but their discussion has 

 at all events procured this incontestable advantage to science, 

 namely, that each of them, endeavouring to support his 

 opinion upon facts, has discovered and explained the internal 

 structure of the seed, and the mode of germination of many 

 plants which had been scantily or badly observed in this 

 respect. As a general thesis, however, we shall venture to 

 •ay, that we never can be sure of the constancy of a cha- 

 racter, so long as its importance is not demonstrated by the 

 kind of influence which it exercises ; for every thing which 

 rests only on simple empirical observations, however nu* 

 inerous they mav be, may be overturned by a single observa- 

 tion of a contrary tendency. Now the influence of the 

 number and of the various forms of parts in vegetables, is 

 Jtill too little known to entitle us to hope, for a long time^ 

 to give to botanical characters that degree of rational cer- 

 tainly which tjiose of zoologv have obtained. 



We 



