on certain stony and metalline Substances , See. 207 
or cellular part, similar, in every respect, to the specimen 
already described, and every where completely connected with 
the substance of the mass itself. 
If the compact part of this piece is examined with attention, 
it will be perceived, that it is not entirely composed of iron in 
the metallic state, but that it is mixed with nearly an equal 
quantity of the transparent substance of a yellowish green 
colour, (sometimes also of a greenish yellow,) already spoken 
of in the description of the other specimen. This substance is 
mixed with the iron, in such a manner, that if the whole of the 
former could be removed, the remaining part would consist 
merely of iron in the metallic state, and would present the same 
cellular appearance as the preceding specimen, and the ramified 
or cellular part of the specimen now described. 
This stony part, separated from the iron, appears in the form 
of small nodules, generally of an irregular shape, but sometimes 
nearly globular : they have a perfectly smooth and shining 
surface, so as very often to present the appearance of small 
balls of glass ; a circumstance that has led many persons to 
suppose them the result of a real vitrification. Some of these 
nodules have several irregular facets, produced by the com- 
pression of the iron in which they were inclosed ; but I have 
never observed in them, any appearances that could lead me to 
suspect they had the slightest tendency whatever to assume a 
determined crystalline form. 
This substance is always more or less transparent. It is suffi- 
ciently hard to cut glass ; but has no effect upon quartz. It is 
very brittle : its fracture is usually conchoid ; but I could not 
perceive that it broke in any particular direction, in such a wav 
that I could consider the fracture as a natural one. It becomes 
