METEORITES OF NORTH AMERICA. 175 



From the edge of side F, which shows comparatively slight oxidation, three indistinct veins run into the meteorite. 

 They are black, indefinite in outline, and somewhat branching. 



A petrological analysis by W. Harold Tomlinson of Germantown, Pennsylvania, shows that the mineral constituents 

 are olivine and enstatite. Some pyrrhotite was also found. Mr. Tomlinson remarks: "The olivine and enstatite occur 

 both as grains and as chondri. The grains of olivine contain frequent inclusions of smaller grains and of iron, and 

 occasionally have gaseous inclusions. The inclusions in the enstatite are generally parallel to the cleavage." He 

 found the specific gravity to be 3.60. 



CHEMICAL ANALYSIS BY JOHN M. DAVISON. 



The specific gravity of the Estacado aerolite is 3.63. The metallic part was separated with a magnet and the slight 

 amount of adhering stony matter determined and deducted. 



The stony part was separated by hydrochloric acid into a soluble and an insoluble portion. The. insoluble portion 

 was digested with a solution of NajCO 3 and the dissolved SiO 2 added to that dissolved by HC1. This analysis gave: 



Metallic 16.41 



s (Soluble in HC1 4L 09 



(Insoluble in HCL. . 42.50 



100.00 

 Analyses of these, omitting minor constituents and calculated to 100, gave: 



Metallic. Soluble in HC1. Insoluble in HC1. 



Fe 89.45 SiO, 32.00 SiO 2 63.57 



Ni 9.99 MgO 32.02 MgO 23.45 



Co 0.56 FeO 3L 60 FeO 9.54 



CaO.. 4.38 CaO.. 3.44 



100.00 



100. 00 100. 00 



The stony part appears to be mainly olivine and enstatite. The analysis of the entire mass gave the following 

 percentages: 



Fe 14.68 



Xi : L60 



Co 0.08 



Cu Trace. 



C (found but not determined). 



S L37 



P a 15 



SiO 2 35. 82 



FeO 15.53 



MgO 22.74 



CaO 2. 99 



AljO, 3. 60 



Na,O 2.07 



KjO 0.32 



TiOj, Cr 2 Oj, and MnO (found but not determined). 



100.95 

 Lees O for S... .68 



100.27 



Of the S found 0.82 per cent came from the metallic and the portion soluble in HC1, and 0.55 per cent from the 

 insoluble portion fused with NajC^. In this fusion the crucible was screened by a close fitting asbestos board and a 

 blank experiment showed that there was no contamination from the gas flame. This distribution of the S would 

 indicate that nearly half of the troilite was embedded in the enstatite protected from action of acids. 



From 3.9597 grams of the aerolite 0.025 gm. of chromite was separated by repeated treatment with HF and other 

 acids. With the chromite were a few minute particles of a transparent colorless mineral that had survived this usage 

 though evidently attacked. Search was made for ZrO 2 , with negative result. 



BIBLIOGRAPHY. 



1. 1906: HOWARD. Estacado aerolite, preliminary notice. Amer. Journ. Sci., 4th ser., vol. 21, p. 186. 



2. 1906: Ho WARD ^nd D AVISO \ T . The Estacado aerolite. Amer. Journ. Sci., 4th ser., vol. 22, pp. 55-60 (analyafe 



and illustrations). 



