414 Proceedings of the Royal Physical Society. 
may be simply dependent on the rapid cooling, or any other 
cause which gives the iron its brittle character. Another patch 
of etching was made near the narrow extremity of the pointed 
portion of the mass (fig. 2). Here the crystalline structure 
of crossing lines is less distinct, the metal being apparently 
more granular in its texture, and exhibiting a series of shining 
points. The action of the diluted acid on the metal was closely 
watched, and was stopped occasionally, so as to preserve the 
appearance of the etching, when its character was most dis- 
tinct. Wax squeezes and electrotype casts were taken from 
these etched surfaces, and are here printed from as woodcuts 
(figs. 1, 2). They may therefore be compared with that figured 
before, which was taken in a similar way from the central part 
of the meteoric iron. 
A portion of this meteoric iron, with plaster cast of the 
entire mass, are now preserved in the Natural History Mu- 
seum, Edinburgh ; the principal part of the iron is in the 
British Museum, London.] 
Analysis of the Mtteorolite described in the foregoing paper by Dr John 
Alexander Smith. By Murray Thomson, M.D., F.C.S , Lecturer 
on Chemistry. 
In giving a chemical description of this remarkable mass 
of meteoric iron, I have to call attention, in the first place, to 
its Specific Gravity ; the process of taking which was first per- 
formed on the undivided meteorite, and afterwards on each 
of its halves. Of course, with such a weighty mass this 
process could not be done by means of the ordinary delicate 
balance. I had therefore recourse to the standard beams and 
weights contained in the office of the Inspector of Weights 
and Measures at the County Hall, Edinburgh. The weight in 
air of the whole mass was 32 lbs., 11 oz., 1 J drs., avoirdupois, 
equal to 39-60 lbs. Troy weight. The weight in distilled 
water was 27 lbs., 10 oz., 13 J drs. This gives a specific 
gravity, it will be seen, of 6-517, which is very low for me- 
teoric iron. It stands at the lowest limit of recorded specific 
gravities of other meteoric irons. Shepard (Silliman*s Ameri- 
can Journal of Science, vol. ii. New Series, p. 377) gives the 
