APPENDIX II. 



MINERALS, WHICH WILL PROBABLY NEVER FORM DISTINCT 

 SPECIES IN THE MINERAL SYSTEM. 



ADHESIVE SLATE. 



Adhesive Slate. JAM. Syst. Vol. II. p. 68. Man. p. 476. 

 Adhesive Slate. PHILL. p. 50. 



Massive : composition impalpable. Principal frac- 

 ture slaty, more and less perfect. Cross fracture 

 even, flat conchoidal. 



Colour yellowish-grey, passing into white and smoke- 

 grey. A little shining in the streak. Feebly 

 translucent on the edges. 



Sectile. Adheres strongly to the tongue, feels a 

 little greasy, and is very soft. Sp. Gr. = 2-086, 

 KLAPROTH. 



It absorbs water with great avidity, but does not fall 



to pieces. On being exposed to a red heat, it becomes 



brownish-red, and loses in weight. It consists, according 

 to KLAPROTH and LAMPADIUS, of 



Silica 66-50 30-80. 



Alumina 7*00 0-00. 



Magnesia 1-50 28-00. 



Lime 1-25 0-80. 



Oxide of Iron 2-50 11-20. 



VOL. III. M 



