METEORITES OF NORTH AMERICA. 65 



Thia analysis makes it very probable that the mineral consists principally of silicious magnesia, with which, how- 

 ever, is mixed a small quantity of calcareous labradorite, disregarding for the latter: 



Ratio of 

 Oxygen. oxygeo. 



Silica 2.657 1.406 6 



Alumina 1. 504 0. 703 3 



Calcareous earth 0.824 0.224 1 



There remains for the first compound 



Silica 65.699 



Magnesia 27.606 



Calcareous earth L027 



Water... 0.683 



95. 015 



Reducing the calcareous earth to magnesia and likewise, after Scheerer, the water to the same basis, ma.t-ing 

 Mg=3H=(H), we have in 100 parts of the mineral 



Computed ac. Mg Si. 



Silica 69.493 69.350-0.143 



Magnesia 30.507 30.650+0.143 



After completing this analysis I noticed that Professor Shepard had already bestowed much attention upon this 

 meteoric stone, and as he was possessed of a very considerable mass of the meteorite he would be able to make numerous 

 investigations, while I had but 200 milligrams at my disposal. 



He announced as the principal ingredient of this meteoric stone a trisilicate of magnesia, without, however, 

 having made an analysis, and named the mineral chladnite, a name which I retained. 



The analysis just given shows, nevertheless, that the chladnite consists of siliceous magnesia (MgSi), and that 

 the meteoric stone is compounded of 95.015 of the same and of 4.985 of feldspar resembling labradorite. 



The chladnite is most closely related to wollastonite (CaSi) among terrestrial minerals, with which the specific 

 gravity, color, texture, hardness, and crystallization closely conform. Small, entirely microscopic crystals, which I 

 distinctly observed, did not show the monoclinic system, and have the form of a figure shown. Specific measurements 

 were not to be had. 



The chladnite is readily cleavable, parallel <x P oo . 



Regarding the chemical relations of chladnite it is to be remarked that I did not omit to test for heavy metal, but 

 no trace of such was obtained. It is possible, however, that the admixture of iron oxide and the grains of magnetic 

 pyrites may contain email quantities of nickel, etc. 



Shepard stated that the Bishopville stone contained hyposulphurous magnesia and sodium, which can be washed 

 out with water. I made this experiment with a very email quantity of material. Traces of calcareous earth and 

 magnesia were noticed in the watery extract, but they were so small that they almost escaped observation and made 

 at best but an extremely small part of the composition of the meteorite. 



The wollastonite belongs to those bodies whose volcanic formation can not be disputed. The most indubitable 

 of these are shown by the great lava stream which lies thick before Rome from the foot of the Alban Mountains to the 

 Capo di Bove and is there used for street paving. The thick gray lava there contains nepheline, leucite, and wollas- 

 tonite, mineral bodies which frequently, in consequence of rapid cooling, can onjy be isolated in crystalline masses, 

 not in distinct crystals. 



I am inclined, therefore, to ascribe to the chladnite the same formation, and conjecture accordingly that this 

 meteoric stone, just after the analogy of the formation and oxidation of the terrestrial bodies we have examined, once 

 was in a state of complete fusion, from which, by cooling, magnetic pyrites, labradorite, and chladnite must have been 

 separated. We are then compelled to concede as important a role to oxygen in the composition of bodies in extra- 

 terrestrial as in terrestrial regions. It is, finally, more than probable that this meteoric mass, upon entering our atmos- 

 phere underwent a second fusion process, in consequence of which the glaze on the exterior of the stone was produced. 



We have a similar terrestrial phenomenon, doubtless never yet described, which is still better suited to support 

 this view. The labradoritic lavas on especially prominent parts of JStna are not infrequently struck by lightning, and 

 upon the exterior, although only in small streaks, they are melted to a glaze which can scarcely be distinguished from 

 the glazed crust of this meteoric stone. 



In 1855 Smith 4 remarked that investigations which he was making seemed likely to show 

 that chladnite was a pyroxene. 



Rammelsberg 5 in 1861 carefully investigated the composition of the meteorite and gave 

 his results as follows: 



This very noteworthy stone fell in March, 1843, in the northern part of Sumter County. Professor Shepard, in 

 his monograph on North American meteorites, gave the approximate circumstances of the fall and the original weight 

 of 13 pounds and described the outward appearance of the stone. Under a black to bluish-gray glassy or porcelain-like 

 crust the interior mass appears of a white crystalline character and, as Shepard expressed it, more nearly resembles a 

 disintegrated albite-granite than a meteoric stone. Shepard gave the name chladnite to this white principal mass. It 

 is distinguished by great brittleness, and it seems as if many places were already altered by weathering. 

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