20 
SALOON, stance, several interesting varieties are deposited 
Nat. Hist, in this Case. 
Case 8 contains principally opaline sub¬ 
stances, VIZ, specimens of the noble opal, which 
owes its beautiful play of colours to a multiplicity 
of imperceptible fissures in its interior ; the sun 
ox jire opal; the common opal, a translucent 
white variety of which, appearing yellow or red 
when held between the eye and the light, is 
called girasol; the semi-opal, agreeing in its prin¬ 
cipal characters with the common ; specimens 
of those varieties w^hich, having the property of 
becoming transparent when immersed in water, 
are called hydrophanes, and vulgarly oculus 
mundi; wood-opal, or opalised wood ; jasp-opal, 
referred by some authors to jasper ; the menilite, 
called also liver-opal, found at Menil-Montant, 
near Paris, in a bed of adhesive slate, a specimen 
of which is added. Some varieties of cacholong 
may likewise be referred to the opal tribe.—The 
remainder of this case is occupied by the siliceous 
substance called hornstone, divided into the con- 
choidal and splintery varieties; among these are 
the remarkable pseudomorphous crystals from 
Schneeberg in Saxony, derived from various 
modifications of calcareous spar, and generally 
referred to conchoidal hornstone; also some 
beautiful specimens of wood converted into 
hornstone, being the wood-stone of Werner ; 
hornstone balls from Haunstadt in Bavaria.— 
Flinty slate, &c. 
Case 
