DALY. — ETCH-FIGURES ON AMPHIBOLES. 381 



Glaucophane. 



*P. 5G. He de Groix. 

 L. 57. 



Barrois, Am. Soc. Geol. du Nord, 1883, p. 19. 

 P. 58. Oulx, Savoy. 

 *P. 59. (Gastaldite) Champ de Praz, Val d'Aosta. 90, 197. 

 Crossite. 



*P. GO. Berkeley, Cal. 

 Riebeckite. 



P. 61. St. Peter's Dome, Colorado. 89, 6. 

 Arfvedsonite. 



*P. 62. Kangerdluarsuk, Greenland. 

 *C. 63. 

 (Barkevikite.) 



*P. 64. Barkevik. 

 Aenigmaiite. 



*P. 65. Naujakasik, Greenland. 95-190. 

 *C. 66. 

 Bronzite. 



*P. 67. Kraubat, Styria. 

 P. 68. Greenland. 9-25. 

 Hypersthene. 



P. 69. St. Paul's Island. 35-2631. 



Lacroix, Min. des Roches, 1888, p. 261. 

 Diopside. 



*P. 70. Ala. 

 A ugile. 



P. 71. Puy de la Rodde. 



Gonnard. Cf. Lacroix, Mine'ralogie de la France, Vol. 1, p. 578. 

 Fowlerite. 



*P. 72. Franklin, New Jersey. 



Methods Used. 



The researches of recent years on figures of corrosion have shown that 

 the most fruitful results are obtained by quantitative methods, that is, by 

 the use of reagents under definite specified conditions, and by close 

 measurement of the figures. It hardly needs mention that there is 

 much yet to be learned regarding the coliesional properties of the 

 species belonging to each of the great mineral groups, as well as re- 

 garding the similar relations which may exist between corresponding' 

 members of two different families. Just as we may describe as accu- 

 rately as possible the hardness or the fusibility, the specific gravity or 

 the optical properties, of a species, not only to fix it as an independent 

 type, but also to relate it to the other members of its own family and 

 to other mineral groups, so we believe it is possible to construct with 



