THE NARRABURRA METEORITE. Dot 
also that from the sections (or from the photographs of the 
sections) it might be possible to build up a model so as to 
show the internal structure and arrangement of the crystals, 
enclosed nodules, fissures, etc., but as it is very difficult to 
recognise parts of the structure as being common to any 
two of the sections, the information obtainable from a 
reconstruction would not perhaps be of much importance 
as Thad hoped. More information would be obtained if 
both sides of each section had been polished and etched, 
but so far there has only been time to do one side of each. 
I do not think this has been previously done for many 
meteorites, the Boogaldi siderite was so treated, but only 
one section was published, see Journ. Roy. Soc. N.S.W., 
1902; as a rule, pieces appear to be indiscriminately sliced 
off for examination, and for exchange or sale; and usually 
only one of them is photographed. In some siderites the 
structure is fairly uniform throughout and they may not 
repay the trouble and expense, but in this instance I think 
that the differences in crystalline structure, distribution of 
nodules, etc., shown on passing from the exterior to the 
interior are worth the extra labour expended in making 
the series of sections, and even if the slices become dis- 
persed the consecutive series of photographs will be avail- 
able for future examination. 
By an oversight all the polished and etched surfaces do 
not face one way. The disposition of the crystals is, in 
part clearly octohedral, but there are other crystals, 
notably some of the large ones, which do not conform 
to this arrangement. 
DESCRIPTION OF THE PLATES. 
Plates 11 and 12 are reproductions of photographs of the 
exterior of the meteorite reduced to one*half of the natural 
size. The dimensions of some of the principal pits and 
