46 MEMOIRS NATIONAL ACADEMY OF SCIENCES, VOL. XIII. 



1.5 to 5 mm. in diameter, the two angles being 60° and 120°, while the triangular markings 

 range from S to 15 mm., with angles of 55°, 55°, and 70°. Troilite nodules are rare The 

 iron is tough, but not more dense than in the majority of siderites. In fact its specific gravity 

 is rather low on account of numerous clefts which permeate it. , 



Brezina 7 describes a section in the Vienna museum received from Castillo as showing 

 lamelhe 0.05 mm. in width, somewhat cracked, fibrous, and appearing to consist only of tsenite. 

 Meshes prominent, plessite dark and full of tsenite points. A cut of the section shows curved 

 lamellae. 



Angermann u states the meteorite lies in a north and south valley and that the rocks of 

 the region are of eruptive origin, belonging to the group of andesites. He further states that 

 the mass was first discovered in 1863 by being struck by a plough. The brilliant surface of the 

 scratches led the people living near to think it might be silver, but a local blacksmith assured 

 them from the character of the rust that it was iron. The priest at Bacubirito informed the 

 people that the mass had come from hell, and advised them not to disturb it. This advice was 

 heeded, and hence no word of it reached the outside world until the mention of it by Barcena 

 in 1876. 



Measurements of the mass are given by Angermann and compared with those of Ward and 



Castillo as follows: 



Ward. Castillo. Angermann. 



Length 3.99 m. 3.65 m. 3.50 m. 



Breadth 1. 9 m. 2. 00 m. 2. 20 m. 



Thickness 1.6 m. 1.50 m. 1.20 m. 



From a specific gravity of 7.69 Angermann calcidates the weight as 25 metric tons = 27.6 

 tons avoirdupois. The fissure in the meteorite Angermann regards as produced by the shock 

 of striking the earth, and thinks that pieces broken off at the time may be found in the vicinity. 



As Whitfield's analysis of this iron showed a loss of 4 per cent, Cohen obtained from Ward 

 material for conducting a new investigation, besides a specimen of some 85 grams weight having 

 a section surface of 14 sq. cm. 



This he describes 10 as forming a section 1 cm. thick with an octahedral boundary in con- 

 formity with which it was very easy to break off fragments, as there were many cracks visible 

 conforming to the above octahedrons. Upon the polished and etched surface the twinned 

 lamella? appeared in thin, ragged edged blades, which are of varying width and as much as 1 

 cm. in length. 



Cohen goes on to say: 



Ranchito consists conspicuously of a fine-grained, dark plessite, with small, shining, evenly distributed scales, 

 which are mainly tsenite skeletons. The fine lamella?, about 0.05 mm. wide, intersect at an angle of 60° upon the 

 section. They seldom lie isolated, but group themselvess as a rule in bundles, which attain a breadth of 0.5 mm., 

 but mostly are much finer. From the macroscopic appearance the lamellae might be supposed to consist of tsenite; 

 under the microscope, however, they are distinctly perceived to be built up of extremely fine-grained kamacite and 

 a tsenite envelope. The bundles of lamellae are quite uniformly distributed, and occasionally so long that they reach 

 clear across the section, while the remainder lie isolated in the plessite. Nevertheless, the areas are in general bounded 

 by quite uniform dimensions, from which fact the etched surface acquires a characteristic aspect. On account of the 

 fineness of the tsenite leaves and the slight distinction between the kamacites of the bands and fields the lamellse are 

 faint in luster and color. 



Analysis (Whitfield) : 9 



Fe Ni Co S P Si 



88.944 6.979 0.211 0.005 0.154 trace =96.293 



Specific gravity (Ward), 7.59 



Cohen 10 criticised the above analysis on account of the loss of nearly 4 per cent shown, and 

 suggested that a meteorite so rich in taenite ought also to show a higher content of nickel. 

 Later he published an analysis with results as follows : 



Fe Ni Co Cu Cr C P S 01 Chromite 

 89. 54 9. 40 0. 98 0. 02 0. 02 0. 01 0. 12 0. 02 0. 02 0. 01 =100. 14 



Specific gravity, 7,580. 



