Specimens from ’Torre del Greco. 
13 
magnetic oxide ; the cavity is lined with minute brownish red 
transparent crystals of oxide of iron. 
No. 19 is a mass, apparently broken from No. 13, in the interstices 
of which are well defined crystals of specular iron ore. 
No. 20 is a mass of iron reduced to the state of crystalline black 
oxide, and differs from all the other specimens, in being possessed of 
magnetic polarity, both in mass and in fragments. 
No. 15 is a mass, probably part of a bar, with lava adherent to it : 
the whole is in the state of magnetic oxide, except a central cylin- 
drical piece a few inches long, and about one-fourth of an inch 
thick. This piece, on being bent backwards and forwards once or 
twice, breaks, and exhibits a completely crystalline structure, with a 
tin white colour and lustre. It has no polarity, but acts powerfully 
on the magnetic needle, and is soluble in muriatic acid, with a copious 
disengagement of hydrogen gas. It is therefore iron in the metallic 
state, having acquired, by the long continued action of heat, a crys- 
talline arrangement, and is probably entirely free from carbon. 
No. 17 is an agglutinated mass of nails. The thicker ones appear 
to have been of cast iron, and are converted into a dark grey oxide, 
the thinner ones appear to have been of bar iron, and are still 
malleable, but in colour and structure resemble the specimen just 
described. 
No. 18 is a key, the central part of which is in the metallic state, 
while the exterior is in the state of red, and of magnetic oxide. 
From this series we may conclude — First. That the proportion of 
free sulphur in the lava, if any, must be very minute, since there is 
not the least appearance of any iron pyrites. — Secondly. That iron, 
by exposure for a sufficient length of time to a temperature by no 
means sufficient to melt it, or even materially to alter its form, may 
be converted either into massive oxide, with a perfectly crystalline 
