ME. N. STOET-MASKELYNE ON THE 
366 
XVI. The Shalka Aerolite. 
In the year 1860 the Hitter von IIaidinger* first gave an account of the very remark- 
able meteorite that fell at Shalka, in Bancoorah, Bengal, on the 30th of November, 1850. 
The ash-like dark grey substance which forms the mass of this meteorite was described 
by the illustrious Viennese authority as a new silicate, to which he gave the name of Pid- 
dingtonite. He was, in fact, led to do this in consequence of an analysis of the mineral 
by K. von Hauer, which yielded oxygen ratios corresponding to “ a compound of bisi- 
licate and trisilicate of iron and magnesium.” 
' This assumed sesquisilicate, however, which has haunted the mineralogy of meteorites 
under the names of Chladnite, Shepardite, and, subsequently, of Piddingtonite, was sur- 
mised by Gustav RosEf to be in this case a mixture of more than one silicate, while in 
the similar instance of the Bishopsville meteorite Dr. Lawrence Smith J had already 
proved the supposed Chladnite to have been no other than an augitic mineral, in fact 
one with the composition and characters of enstatite. The mineral, however, which 
forms the mass of Shalka does not seem to be so easily disposed of; for Professor Ram- 
melsberg § has recently published an analysis of the mineral or minerals under discussion, 
t and asserts the Shalka meteorite to contain something like 12 per cent, of divine of the 
composition 2Fe 2 Si0 4 -(-3Mg 2 Si 0 4 ||, the remainder being bronzite. 
This meteorite had been examined some time back in the British Museum Laboratory 
with a very different result, and the discrepancies between this result and those as well 
of Rammelsberg as of V on Hauer induced me to have the analysis confirmed by further 
investigation. The conclusion, however, to which these experiments have led still leave 
the discrepancy where it was. In fact the selection out of the debris of the meteorite 
of the different ingredient minerals, or what seemed to be such, had at first led to the 
belief that it might indeed consist, first, of a grey silicate ; secondly, a more mottled 
grey and possibly mingled mineral ; and thirdly, chromite, which is present in consider- 
able quantity, and often in very perfect crystals. An analysis, however, of the mixed 
silicates gave a result so nearly in accordance with that of a definite enstatite, that the 
view seemed hardly tenable. Furthermore, the analysis of the mottled variety gave as 
its result that this mineral is no other than bronzite. 
The analysis of a very small amount of the debris of the meteorite gave the following 
numbers : — 
Silicic acid 
. 45-37 
Oxygen. 
24-197 
Iron protoxide .... 
. 19-06 
4-236 
Calcium oxide .... 
. 2-214 
0-632 
Magnesium oxide 
. 15-636 
6-254 
Chromite 
. 17-717 
99-997 
* Ber. Akad. Wiss. Wien, xli. p. 251. 
f Beschreibung und Eintheilung der Meteoriten, p. 125. j Shuman’s Am. Journ. Se. xxxviii. p. 225. 
§ Ber. der Deutsch. Chem. Gesellschaft. Berlin, iii. p. 522. || Pogg. Ann. cxl. p. 312. 
