i86 Mr. Howard's Experiments and Observations 
metallic state, have undergone an oxidizement at their surface; 
a circumstance that has produced a great number of spots, of 
a yellowish brown colour, and very near to each other, over a 
part of its internal substance. This oxidizement, by adding to the 
bulk, and to the force of action, of the part we have described 
as serving by way of cement to the other constituent parts of 
the stone, has occasioned a greater degree of adhesion between 
these parts, and has rendered the substance of the stone more 
compact. 
The great quantity of iron in a metallic state which this 
stone contains, added to its greater compactness, makes it 
capable of receiving a slight degree of polish ; whereas it is im- 
possible to give any polish to the others. When polished, the 
iron becomes very evident, in the polished part ; appearing in 
the form of small specks, almost close to each other, which have 
the colour and lustre peculiar to that metal : these specks are, 
in general, nearly of an equal size. 
The black crust of this stone is similar to that of the others,, 
The specific gravity of the stone is 4281. 
It is easy to perceive, from the foregoing description, that 
these stones, although they have not the smallest analogy with 
any of the mineral substances already known, either of a volcanic 
or any other nature, have a very peculiar and striking analogy 
with each other. This circumstance renders them truly worthy 
to engage the attention of philosophers ; and naturally excites 
a desire of knowing to what causes they owe their existence* 
I proceed to consider the assistance to be derived from 
chemistry, in distinguishing these stones from all other known 
