Penfield and Foote — Composition of Tourmaline. Ill 



Gouverneur, N.Y., Monroe, Conn., Haddam, Conn., Snarum, 

 Brownish- 

 Brown. Black. Black. Black. 

 Em.l. Rgs. 53.* Km.7. Rgs. 51. Rm. 11. Rgs. 47. Rm. 12. J.&C.56. 

 Ti0 2 ... 1-19 1-61 -57 1*10 

 i.'g j SiOa... [35-16] 3739 [36-40] 36-41 [34*75] 3495 [34-56] 35'64 

 5"§ } B 2 8 ... [10-43] 10-73 [10-61] 9 65 [10-14 9-92 [10 08] 9 93 

 * AI2O3.. 31-32 27-79 3118 31*27 30-87 31-11 30-00 29 41 



Fe 2 3 .- '10 -50 2-90 



FeO ... 1-14 -64 4 07 3*80 8-54 1187 11-16 656 



MnO... __ -09 



MgO___ 14-89 14-09 9-90 947 8-60 4-45 7"94 8'00 



CaO 160 2-78 1-81 '98 1-33 -81 -65 165 



Na 2 .. 1-28 1-72 182 2-68 1-60 2*22 113 3-03 



, T3 ) K a O ... -26 -16 -44 -21 '73 '24 -53 -16 



S| >H s O... 3-32 3-83 3*77 3-79 3*44 3'62 363 294 



'■> £ F -55 



•g TO 



fcJDr 



10000 100-42 100-00 99-87 100-00 100 35 100-23 101-32 



SiO a ... 38-85 39-01 3750 37*22 



H 2 0... 2-31 2-82 1-81 164 



Ign ... 3 : 19 3-32 249 2'39 



Alabashka, Brazil, Pierrepont, N. Y., 



Black. Green. Black. 



Rm. 20. J.&C.57. Rm. 32. Rgs. 41. J. & C. 64. Rm. 35. Rgs. 50. 



. TiOa --- *55 



illMSiO, [35-44] 35-41 [35-90] 36 91 37'05 [34-98] 35-61 



o|(B 2 3 [10-33] 10-14 [10-51] 987 909 [10-20] 10-15 



* A1 2 3 ... 30-41 33-75 37-81 38-13 40-03 27*18 25'29 



Fe 2 3 -31 -44 



FeO 15-59 13*42 5'83 319 236 9*08 819 



MnO -54 1-13 2'22 2-35 



MgO 1-83 1*57 -92 -04 -32 10-13 13*07 



CaO -17 -38 *47 2-91 3-31 



Na 2 1*02 2-08 221 2*70 3*18 1*50 1*51 



K 2 *47 *34 *42 *28 *20 



, -o ) Li 2 0_ 1-30 1-61 -60 



g-2 lH 2 3-88 3*41 3*57 3*64 3*23 4*02 3*34 



Op\F„ '76 *28 *70 *14 1*15 *27 



100-32 100-57 100-30 99*42 9983 10000 99-93 



(Si0 2 36 19 38-06 36*64 



\ H 2 I'll 2-23 3-01 



O ° (Ign 2*15 2*92 ? 



With the present interpretation of Rammelsberg's analyses the 

 ratios of Si0 2 : B 2 3 have been assumed as 4:1, while those of 

 Si0 2 to the total equivalent of hydrogen atoms in the different 

 analyses are as follows : 



No. 1 



No. 7 



No. 11 



No. 12 



No. 20 



No. 32 



No. 35 



4 :20*7 



4:19-8 



4:20-5 



4:20-06 



4:19-6 



4:39*9 



4:20-2 



-•Compare the reference to this analysis on p. 115. 



