120 Penfield and Foote — Composition of Tourmaline. 



03 



E 

 c 1 



EH 



o — 

 En <n 



&| 

 cS © 



§ s j 



Mg& 

 Fe. 



Locality. 



Minas Geraes, Brazil . . . 



Rumford, Me. 



Brazil 



Auburn, Me 



Minas Geraes, Brazil 



Schuttenhofen, Bohemia 

 Haddam Neck, Conn. . . 

 Barra do Perahy, Brazil. 



Rumford, Me... 



Minas Geraes, Brazil... 



Auburn, Me 



Schuttenhofen, Bohemia 



Auburn, Me 



Buckworth, Australia.. 



Paris, Me 



Auburn, Me 



Alabashka, Russia 



Mursinka, Russia. . 



Schuttenhofen, Bohemia 



Piedra Blanca 



Montgomery Co , Md. . _ 



Minas Geraes, Brazil 



Stony Point, N. C 



Olahpian 



Tamatawe 



Haddam, Conn . 



Snarum, Norway ... 



Orford, N. H 



Monroe. Conn. 



Nantic Gulf, Baffin's Ld. 



DeKalb, N. Y 



DeKalb, N. Y 



Gouverneur. N Y 



Hamburg, N. J 



Pierrepont, N. Y._ 



Color. 



Analyst. 



Pale-pink . 



Rose 



Green 



Colorless _ . 

 Pale-green 



Red 



Pale-green . 



Green 



Dark -green 



Olive-green 



Light-green 



Blue-green 



Dark-green 



Black 



Black 



Black 



Black 



Black 



Blue-black. 



Black 



Green (Cr) 



Black 



Black 



Black 



Black 



Black 



Black 



Dark-br'wn 

 Dark-br'wn 



Black 



Colorless . . 

 Colorless . . 



Brown 



Brown 



Black 



Riggs, 37 



Riggs, 36 



Jann. & Kalb, 64 



Riggs, 38 



Riggs, 39 



Scharizer. 61 ... 



Authors 



Jann. & Kalb, 63 



Riggs, 42 



Riggs, 41 



Riggs, 40 



Scharizer, 66.. _ 



Riggs, 43 



Jann. & Kalb, 62 



Riggs, 44 



Riggs, 45 



Jann & Kalb. 57 

 Jann. & Kalb, 60 

 Scharizer. 65... 

 Jann. & Kalb, 58 



Chatard, 72 



Riggs, 46 



Riggs, 48 



Jann. & Kalb, 61 

 Jann. & Kalb. 59 



Riggs, 47 



Jann. & Kaib. 56 



Riggs, 52 



Riggs, 51 



Riggs, 49 



Authors 



Riggs, 54 



Riggs, 53 



Riggs, 55 



Riggs, 50 



6-7 

 6-5 

 6-3 

 0-2 

 62 

 6-1 

 6-1 

 6 

 6-0 

 5-9 

 5-7 

 5-5 

 5-3 

 4-7 

 4-7 

 4-7 

 4-7 

 4-7 

 4-5 

 44 

 4-4 

 4-3 

 4-2 

 40 

 3-8 

 3-7 

 3-7 

 3-6 

 3-4 

 3-1 

 25 

 2-2 

 2-2 

 2'0 



1-6 



K' H 



0-3 



0-2 

 1-1 

 0-6 

 08J 



o-3: 



1-1 



1-1 



1-3 



1-1 



09 



1-2 



1-5 



2-9 



3-0 



3-1 



3-2 



32 



3-0 



3*2 



34 



3-5 



36! 



4-1 j 



4 6; 



4-0 



4 4 



4-1 



4-1 



4 7 

 57 



5 7 

 5 6 

 6'2 



63 



1-2 



1-2 



0-9 

 1-1 

 1-3 

 1-3 

 1-2 

 1-4 

 11 

 1-3 

 1-2 

 1-2 

 11 

 0-7 

 0-5 

 0-5 

 0-5 

 0-7 

 0-5 

 0-6 

 0-5 

 0-5 

 0-5 

 0-5 

 0-5 

 05 

 0-7 

 0-6 

 0-7 

 0-5 

 0-3 

 0-4 

 0-4 

 0-2 



0-4 



0-8 

 1-1 

 0-7 

 1*1 

 0-7 

 1-3 

 0-6 

 0-5 

 0-6 

 0-7 

 1-2 

 l'l 

 11 

 0-7 

 0-8 

 0-7 

 0-6 

 0-4 

 10 

 0-8 

 0-7 

 07 

 0-7 

 04 

 0-1 

 0-8 

 0-2 

 07 

 0-8 

 07 

 05 

 0-7 

 0-8 

 0-6 



0-7 



It will be observed that the extent to which the nine hydro- 

 gens of the acid H 9 Al 2 (B.OH) a Si 4 19 are replaced by metals, is 

 very variable. The trivalent metal, R //; , is chiefly aluminium, 

 and the extent to which the hydrogens are replaced by it 

 ranges from 6*7 to 1*6. The bivalent metals represented by 

 R" are chiefly iron and magnesium, and the extent to which 

 the hydrogens are replaced by them ranges from 0*2 to 6*3. 

 In general R" and R /r/ are reciprocal. There is always some 

 hydrogen replaced by the alkali metals R', and some basic 

 hydrogen. The results are arranged in the table according to 

 a decrease in the replacement of the hydrogens by R'", and 

 according to this arrangement the different varieties of tour- 

 maline fall into natural groups. 



The first 13 examples are characterized by containing an 

 appreciable quantity of lithium, while in the others none, or 



