20 
SALOON. 
Nat. Rist. 
Case 8 contains principally opaline sub- . 
stances, viz, specimens of the noble opal^ which i 
owes its beautiful play of colours to a multiplicity | 
of imperceptible fissures in its interior; the Mex¬ 
ican sun ov Jire opal s the common opal^ a translu¬ 
cent 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 which, having the property of be¬ 
coming transparent when immersed in water, are 
called hydrophanes, and vulgarly oculus mundi; 
voood-opal^ or opalised wood asp-opal^ referred 
by some authors to jasper; the meniUte^ called also j 
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 divided into the conchoidal and ! 
splintery varieties; among these are the remark¬ 
able pseudomorphous crystals from Schneeberg 
in Saxony, derived from various modifications of 
calcareous spar, and generally referred to con¬ 
choidal horn-stone; also some beautiful sped- i 
mens of wood converted into horn-stone, being l 
the of Werner; horn-stone balls, from : 
Haunstadt in Bavaria.— Flinty slate ; 
Case 9. In this case are deposited (besides | ■ 
the specimens of rock crystals continued from 1 1 
the opposite compartment of the table-case) the i i 
different :i 
