22 Mr. Glassford on the Electric Light. 



Carbonate of lime, 24-00 21-20 



Carbonate of magnesia, 4-62 2*85 



Water & carbonic acid, 1"75 4*89 



100-00 100-00 



These analyses are confirmatory of the views stated in my former paper, 

 and bear out the principal points in Mr. Macadam's report ; they seem 

 clearly to establish the new and remarkable fact, that by the igneous 

 action in these localities in Bute, magnesia has been driven ofiF from the 

 limestone. The unaltered rock is a dolomite, containing nearly 70 per 

 cent, of carbonate of lime, and nearly 20 per cent, of carbonate of mag- 

 nesia; while the altered rock contains no more than 1 or 1^ per cent, of 

 the latter ingredient. To what cause are we to assign the changes that 

 have taken place? Has the magnesia been sublimated by the action of 

 the trap dike when fluid under the influence of heat"? or has it been with- 

 drawn by the solvent power of free carbonic acid, after the consolidation 

 of this matter from a state of igneous fusion? On the nature of these 

 and the other chemical changes that have been induced, and on the precise 

 character of the metamorphic action, it is unnecessary that I should make 

 any additional remarks, the subject having been, perhaps, as fully treated 

 of in my former paper, as my own knowledge of theoretical chemistry, and 

 our present limited acquaintance with facts, will permit. The subject is 

 one of great interest, both to the geologist and chemist, as the facts are 

 directly opposed to the received views, {Daubeny on Volcanoes, 2d Edit. 

 1849,) and as no instance of similar changes on dolomitic rocks has, so 

 far as I am aware, ever been put on record. It is hoped that the publi- 

 cation of these analyses may lead to a similar examination of dolomitic 

 rocks placed under like conditions, and that thus, by an extended inquiry, 

 materials may be collected for establishing the true theory of the chemical 

 changes which these rocks have undergone. 



17th January. — T7ie President in the Chair. 



The following gentlemen were admitted, viz. : — Messrs. James Stevens, 

 William Johnson, and David Y. Stewart. 



On the motion of Mr. Cockey, seconded by Mr. Bell, it was agi-eed that 

 the entire Catalogue of the Library, now nearly exhausted, should be 

 printed, instead of a supplement only, as was formerly proposed. For 

 this purpose £7 was voted for the first time. 



Mr. Glassford explained and exhibited the new method of applying 

 electricity to the purpose of illumination. Mr. Glassford, in conjunction 

 with Mr. R. Finlay, philosophical instrument maker, had constructed a 

 very extensive and powerful galvanic battery, upon the Maynooth principle, 



