26 MEMOIRS NATIONAL ACADEMY OF SCIENCES, VOL. XIII. 



bersite continue through them all; in addition, however, three typical nodules of troilite were encountered, which 

 contrast strongly in color and form with those in which the schreibersite forms a prominent part. The sections etch 

 very slowly; in time, however, lines appear which I did not hesitate to call Neumann lines until Mr. Tassin proved 

 the iron to be an octahedrite, as was at first indicated by the fracture. These lines do not cross the veins referred 

 to, and they are differently oriented in each of the blocks outlined by these veins, making the blocks appear as separate 

 units. Mr. Tassin finds the structure of this iron to be unique, although in general appearance — especially in the 

 irregular graphic segregations of schreibersite and troilite — it very closely resembles the Sao Juliao, and iu a less degree 

 the Tombigbee River, and in some respects the Kendall County. 



Mr. Wirt Tassin of the United States National Museum has devoted considerable time to the study of this iron and 

 gives a summary of his results as follows: 



"The iron here described is triangular in outline and shows a well-marked octahedral fracture on one edge, in 

 fact the three edges of the section approximate three directions of an octahedron with the cut surface forming a fourth, 

 giving the mass as a whole the appearance of a flattened octahedron. The surface as cut shows octahedral lamella? 

 of the largest size, so large that they are not at once apparent, as the specimen is not big enough to contain more than 

 a few of them. Careful etching develops a surface having in places a mottled or dappled appearance. These mottlings 

 when magnified under a vertical illumination show a definite octahedral structure and an etch figure directly com- 

 parable with that of other octahedrites, and may be regarded as centers of crystallization, which though minute, possess 

 a well-defined lamellar structure and usually show the three characteristic alloys. The accessory constituent, shown 

 in the figure as rows of crystals in relief, is unknown but is here assumed to be nickel-free iron. Such a structure, a 

 most coarse octahedrite containing very minute octahedrites, has never before been observed by the writer. Contained 

 in the mass as a whole are irregularly shaped segregations of troilite, in forms suggesting graphic characters. These 

 troilite areas contain more or less carbon with grains of nickel-iron and phosphide of iron and they are commonly bounded 

 with a thin wall of schreibersite. This compound also appears abundantly elsewhere on the surface, usually as bright 

 points which, under the microscope, appear to be cross sections of the lath-like form known as rhabdite. 



"The surface is also marked by veins or fissures of varying widths, certain of which are parallel to the several 

 directions of the octahedron and form octahedral partings. These veins are commonly bounded by schreibersite and 

 are filled with a carbonaceous material containing phosphorous, sulphur, and iron. 



"The material available for analysis gave the following values: 



Iron 92. 22 



Nickel 6. 49 



Cobalt 0. 42 



Copper '. 0. 01 



Phosphorus .- -0. 28 



Sulphur 0. 07 



Chromium —0. 01 



Silicon 0. 049 



Carbon 0. 09 



99. 639 



BIBLIOGRAPHY. 



1. 190S: Howell. Two new meteorites. Science, n. s., vol. 27, 1908, p. 27. 



2. 190S: Howell. The Ainsworth meteorite. Amer. Journ. Sci., 4th ser., vol. 25, 1908, pp. 105-107. 



ALGOMA. 



Kewaunee County, Wisconsin. 



Latitude 44° 35' N., longitude 87° 25' W. 



Iron. Medium octahedrite (Om) of Brezina. 



Found 1887; described 1905. 



Weight 4 kgs. (9 lbs.). 



This meteorite has been described wholly by Hobbs ' as follows: 



The meteoric iron which is here described was plowed up in the spring of 18S7 on the farm of Mr. Henry Runke, 

 about 4 miles west of Algoma post office, Almapee township, Kewaunee County, Wisconsin. The man who was guid- 

 ing the plow noticed the heavy metal as it was turned up by the plow from the depth ofbut a few inches. Mr. Richard 

 Runke, son of the farmer, was present and reports that the hired man placed the object upon a large stone and struck 

 it a number of blows with another stone used as a sledge, in an attempt to break it. The evidence of this maltreat- 

 ment it bears in a series of dents, especially upon its convex surface. Subsequently it was vigorously attacked with 

 cold chisel -and hammer. A curiosity merely, the Algoma iron remained about the farm on which it was found until 

 March of the present year (1902), when Mr. Richard Runke, now a graduate of the University of Wisconsin and 

 teacher of science in the Madison High School, brought it to the writer for examination. On being told that it was 

 a meteorite and of considerable scientific value Mr. Runke very generously presented it to the university. 



The spot at which the meteorite was plowed up can be located within a few feet, because of its proximity to a large 

 pile of bowlders upon the lot. Mr. Runke has made some search in the vicinity and has also made extensive inquiries 



