300 
NATURE 
[JUNE ©, 1912 
Many eutectics take the form of masses presenting 
the appearance of single crystals, until found under a 
sufficiently high magnification to possess a duplex | 
structure. Such masses have been termed by | 
Benedicks ‘‘colonies,’”’ and are well seen in Swedish | 
white pig iron. Fig. 3 represents portions of three 
such colonies in phosphor-copper, from which it is 
seen that each colony is in reality a spherulitic inter- 
growth of two constituents. 
It may be said that the study of the formation and 
structure of crystallites and eutectics begins where 
geometrical crystallography leaves off. The labours 
of crystallographers have succeeded in bringing the 
geometrical branch of their science to a condition of 
remarkable perfection, but far less progress has been 
Fic. 3 —Eutectic colonies in phosphor copper. 
made in other departments of the study of crystals. 
For example, the causes which determine differences 
of crystalline habit are very imperfectly known. The | 
beauty and diversity of form of natural minerals owes | 
as much to differences of habit as to crystalline | 
symmetry proper, but the former condition has, prob- 
ably from its seemingly capricious character, con- 
trasting with the severe regularity of the latter, 
attracted far less attention from workers on_ this 
subject. 
Tt is evident, also, that a complete molecular theory, 
of crystals must take into account the conditions 
which influence habit as well as the simple geo- 
metrical arrangement of the component 
particles. The study of crystallites and 
eutectics naturally connects itself rather 
with this obscure branch of the sub- 
ject than with the geometrical study. Whether 
crystallites are to be regarded, in accordance with the 
views of some who have written on the subject, as 
embryonic crystals, or whether they should rather be 
considered as crystals thwarted in their development 
by external conditions, their relation to normal 
crystals is an interesting one, whilst their import- 
ance as elements in the structure of metals affords 
ample justification for their study. The progress of 
metallography shows us how greatly the purely 
scientific study of such questions of molecular 
arrangement may influence technical practice, and 
the increasing stringency of the demands made on 
technical metals and alloys calls for a minute investi- 
NO. VOL. 89] 
2222 
2223, 
Edge of section 
gation of the relations between the crystalline strue- 
ture and the physical. and mechanical properties. 
The question has therefore both a theoretical and a 
practical importance, in addition to the fascination 
possessed by all problems bearing on the form of 
natural objects, whether organic or inorganic, the 
study of which constitutes morphology in the widest 
sense of the word. 
SINHALESE IRON AND STEEL OF 
ANCIENT ORIGIN.1 
jy this paper some interesting specimens of ancient 
Sinhalese iron were described. These consist of 
a chisel from Sigiriya, dating back to the fifth cen- 
tury A.D., a nail from Sigiriya of 
about the fifth century a.p., and a 
native billhook, or ‘‘ Ketta.”’ 
From the results of the examina- 
tion of these specimens it would 
appear certain that more than a 
thousand years ago there prevailed 
a knowledge of the metallurgy of 
iron, That a knowledge of harden- 
ing the cutting edges of tools was 
possessed is shown by the ancient 
chisel, which would appear to have 
its edges cemented and carburised. 
It would also seem that the crucible 
process of manufacturing steel has 
been known in the East for a long 
period, and that our modern belief 
that this process originated in 
Europe is probably not correct. 
This Indian industry is now almost 
extinet, owing to the fact that steel 
can be imported from Europe more 
cheaply than it can be manufactured 
locally. 
Reference was made to the collec- 
tion of ancient specimens of iron 
and steel (1200 to 1800 years old) in 
the Colombo Museum, . which is 
probably the most complete of its 
kind in the world, that is, with regard to ancient 
iron. J 
Bearing upon this subject of Indian metallurgical 
Edge. of section 
Point (worn down) 
Fis. Longitudinal section. Magnified 
1.—Chisel, from point. 
80 diameters. 
knowledge, two papers were mentioned on Indian 
steel contributed by Mr. J. M. Heath to the Royal 
1 Abstract of a paper read before the Iron and Steel Institute by Sir 
Robert Hadfield, F.R.S. 
