11 
Specimens from Torre del Greco , 
becoming actually united or incorporated, although some of the pieces 
are more or less vesicular. Externally they are partly of an opake 
white and partly of a dingy purple ; the interior surface of the 
vesicles being also of this latter colour ; the recent fracture exhibits 
a very pale sea green colour, passing into yellowish, and trans- 
parent, but with little or no lustre ; the structure is confusedly, and 
divergingly radiated, resembling considerably the commoner varieties 
of Prehnite. The external surface, in many parts, presents stellated 
groups of minute shining white crystals. Its hardness is such that 
it scratches glass with great ease ; it yields, however, to the file. 
No. 5 shows the ultimate degree of change, the structure having 
become cellular, and the fracture compact. 
Nos. 6 and 7 are specimens of glass which have actually under- 
gone fusion, and are converted into more or less cellular masses, en- 
veloping pieces of lava and other matters. The structure and 
general appearance of these differ much less from that of ordinary 
glass than the specimens above described. 
No. 10 is a parcel of small glass beads, the form of which is but 
little altered, although they have been agglutinated together, and the 
structure has become cellular. 
No. 8 is a cellular slag of a dirty brown and yellowish colour, the 
origin of which is not very apparent : perhaps it has been produced 
by an intimate mixture of glass and of lava. 
No. 9 is a fragment of common pottery. The blue vitreous 
glazing has become more or less cellular, but the pottery itself has 
undergone no change. It may also be mentioned that in No. 6, 
already described, a piece of porcelain is inveloped in the glass ; this 
fragment does not appear to have been in the least degree softened, 
but its fracture displays a more granular structure than ordinary, and 
a glimmering lustre. 
s 2 
