On a Mass of Meteoric Iron. 
403 
its longest diameter. Its hardness, as shown by a graving 
tool, was greatest next its outer surface — the inner portions 
being apparently softer, and more open in texture, while the 
prism-like point was tougher before the tool, and more like 
hammered iron ; the explanation probably being — that this 
peculiarity was due to the shock of the fall being given prin- 
cipally to this part of the mass ; and also, to its being sud- 
denly cooled by the contact of its surface with the earth in 
which it was found buried. 
_ The filings, of which about a troy ounce were procured, 
were black, and showed little of the shining metallic appear- 
ance of pure iron. 
Chemical Analysis. — The filings were sent for examina- 
tion to Dr Murray Thomson, who gives details of their com- 
position in his subsequent communication. (See Analysis of 
Meteorolite, by Dr Murray Thomson.) 
Test of Etching by Acid. — Each portion of the iron has 
been partially etched with the acid used by engravers on steel, 
which consists of equal parts of nitric and acetic acids ; and 
the etched surfaces show the raugh, irregular, projecting lines 
of the crystalline structure of the mass, which have been 
apparently but slightly acted on by the acid, from the pre- 
sence of nickel ; the dark lines and spaces showing where the 
acid has acted with greater eff*ect The acid was applied in 
<the usual way for etching, and appeared to bite all at once, 
and that pretty deeply ; it was then removed, the surface of 
the metal washed, and the acid reapplied, when it acted very 
slightly, and soon ceased to act altogether, not biting any 
deeper into the surface of the metal. The rough etched sur- 
face is characteristic of meteoric iron, various bright lines or 
points being observed in the fine frosted like appearance of 
the crystalline or fibrous surface of the metal. This etched 
surface is finer and more minute in its texture than that of 
any meteoric irons, the etchings of which I have been able 
to examine, suggesting a more minute subdivision of the 
particles of the iron and nickel, and a more general mixture 
of the nickel through the mass.* 
^ Mr R. P. Greg of Manchester informs me this minute texture resembles 
the structure of the iron also found in Britain, and described by him, — more 
