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February 20, 1856. 

 Dr. Charles T. Jackson, Vice-President, in the Chair. 



Dr. C. T. Jackson read the following paper on the 

 Chemical Analysis and comparison of Serpentine Marbles 

 known under the name of Verd Antique : — 



Having made the original geological surveys of the great 

 masses of Serpentine Marbles, vv^hich occur in the northern part 

 of the State of Vermont, and described such as would furnish a 

 marble identical with the celebrated Verd Antique of Europe, I 

 have since been requested to institute a mineralogical and chem- 

 ical comparison of the European and Vermont varieties. 



The results to which I have arrived possess some scientific as 

 well as practical interest, for they not only show a curious re- 

 placement of carbonate of magnesia for carbonate of lime, the 

 magnesite being most abundant in the Vermont marble, while 

 calcite is the predominant spar in the European variety. It has 

 also been ascertained, by experiments made by me some years 

 since, that the Vermont Serpentine marble, and that mixture 

 called Verd Antique, are uncommonly durable, resisting not only 

 atmospheric agencies, but also the action of acids, and, to a 

 remarkable extent, that of fire. 



Dr. Hayes, in an interesting report on this marble, has con- 

 firmed these results, and I am happy in being able also to verify 

 his analysis of some of the magnesite veins, while I also add 

 now some new analyses of other veins in the Vermont marble, 

 and of the calcite of the European Verd Antique. I offer like 

 analyses of the serpentine of the Verd Antique, both of Europe 

 and Vermont, showing their identity of composition, and also an 

 analysis I made many years since of the softer serpentine of 

 Lynnfield in this State. 



Serpentine consists essentially of hydrous silicate of magnesia 

 and silicate of the protoxide of iron, with occasionally a little 

 oxide of chromium — these oxides giving the green color to the 



