232 _ J. D. Dana on the Isomorphism and 
6. Wernerite—W olff’s analysis of a Pargas variety pet very closely with 
bus Si+-241 Si (although referred to the above Wernerite formula by Rammelsberg.) 
3 Si 1731-93 6. atoms of acid and bases,7. ¢. atoms of a 26. 
2X1 12836 A. 871851+2°712 P er) — 2 
20a 70298 B. 13711+7=196 11-+26=527 
a. At. weight, 3718°51 
Idocrase has its vertical axis to that of Scapolite as 5: 4, and 
Zircon to that of Idocrase as 6:5. For comparison we here in- 
sert the atomic volume of Idocrase 
2 Si=1154-62 4%. atoms of acid and bases, 6. c. atoms of elements, 19. 
Al 16 
1 6418 A. 2883" saat (sp. eee 
3a 9373 3B. 848 16-6=141° 848'16+19==44'64 
Fe 150 
a. At. weight, 2883-72 
The atomic volumes of Conetine, Idocrase and Zircon, are as 54: 44°64: 41°05. 
XV. Tale—Different gi ga ise F Sit, Mg Sis, Mg Si. 
1. 48i 230924 ba of acid and base, 7. ¢. —_ + elements, 22. 
3Mg 7635 A. 8072°74+2°7 (sp. gr.) =1 
B. 1138—7—=162°57 C: ease 
a, At. weight, 3072-74 E 
2. 5 Si 2886-55 6. atoms of acid and base, 9. c. atoms . elements, 28. 
4Mg 1018-0 A. 3904°55-+2"7 (sp. er) =144 
B. 1446—+-9=160°7 ee 64 
a. At. weight, 3904-55 e 
8. 1 Si = 57731 6. atoms of acid and base, 2. ¢. atoms of elements, 6. 
1Mg 2545 A. 831°81+2-7 (sp. gr) =308'1 
——  B. 3081+2=154 308:1+6=51'35 
a. At. weight, 831-81 
XVL_ Epidote R2 a - anh 2(R3 8i+#8 Si) +H of the Ural; 
i+# SiH, of Hitteroe. 
Orthite has been shown . Kokscharoy (Min. Ges. St. Petersb, 1847, p. 147, and 
this Sora [2], viii, ~_ to have the crystallization of Epidote. M:T in Epidote 
==)j4° 9 os in Ural e 114° 55’ Kokscharov; in Cerine 116° Rose. The above 
formulas o f Orthite + are Yh peg by Rancnale berg, (Boggpendostf! s Annalen, 
Ixxvi, 98, 1849.) This author also calculates the atomic yolume corresponding to 
he specimens analyzed, and obtains for Epidote having the formula 0 Si)+ 
2(¢A1+4-4¥e) Si, the atomic weight 4309°53, and 4309°53--3°4 (sp. gr.)}=1268 
For Orthite of the Urals (in which 6R=1-2 Fre-f9- 4(Ge, La)+2-4 ba: and of=1: ‘Al 
+05 Pe), the atomic weight 691182; and 6911-°82-—-3598=1921. 
For the Orthite of Hitteroe, in which 3R=0°6 Pe41- 2 Ge+12 Ca; and H=07 
A1+0°3 Fe, the atomic weight 3513-72; and 3513°72--3'459 (sp. gr.) =1017. 
Rammelsberg thence abe that the atomic volumes of these minerals are as 
1:1°5:0°8, “ or perhaps” as 
If, however, as iclitocs we divide the aggregate atomic volume obtained by 
Rammelsberg by the number of atoms of the elements, we 0 
1. For Epidote 1268——-28=15°285 
For Orthite of the Urals 19214048025 
8. For the Orthite of Hitteroe ‘ 1017--21=48'43 
