THE MINERALOGY OF SCOTLAND. 



357 



Brought forward, 







70-683 



Ferrous Oxide, 







2-071 



Manganous Oxide, . 







•078 



Lime, ..... 







23-336 



Magnesia, .... 







trace 



Potash, 







■566 



Soda, ..... 







1-056 



Water, ...... 







2-412 



Insoluble silica, 1-55 per cent. 



100-202 



2. From an adjacent quarry ; the mineral being very similar, but the matrix was 

 quartz. The specific gravity is 3*014. 

 On 25 grains — 



Silica, . 



! 41-56 



Alumina, 



29-901 



Ferrous Oxide, 



3-205 



Lime, 



22-142 



Magnesia, 



-332 



Potash, . 



-345 



Soda, 



-684 



Water, . 



2-19 



100-359 



Insoluble silica, 2-31 per cent. 



3. From the same quarries, but in large crystals of about 2 inches by 1^. These 

 large crystals were lying loose in the quarry, the calcite having apparently been dis- 

 solved away by rain. They were slightly browned on the outside, but lustrous when 

 broken. Three determinations of the gravity gave 3*312, 3*322, 3-318. 



On 1*301 grammes — 



Silica, . 



. 48 



from Alumina, . 



. -034 





•514 = 39-508 



Alumina, 



30-827 



Ferrous Oxide, 



2-52 



Manganous Oxide, . 



•077 



Lime, 



22-813 



Potash, . 



•681 



Soda, 



•9 



Water, . 



2-505 



99-831 



Insoluble silica, 2-334 per cent. 

 VOL. XXXIX. PART II. (NO. 11). 



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