METEORITES OF NORTH AMERICA. 375 



of that metal with sulpuhr, to form the proto-sulphuret of iron, a substance whose mechanical admixture, in a slight 

 degree, with this mineral was sufficiently evinced by our first experiments. 



I am aware that the difference in composition between the specimens just examined, and those of the chrysolite 

 analyzed by Klaproth and Stromeyer may seem opposed to the idea of their specific identity; perhaps it might really 

 be so in a chemical system, but their strong affinity in natural properties certainly proves them to belong to the same 

 mineralogical species — the only difference between the common chrysolite and the present substance being that the 

 former possesses a livelier color, a higher luster, and in general a more perfectly conchoidal fracture, though even this 

 disagreement is not always observable for fragments are occasionally met with in the Virginia aerolite which it would 

 be impossible to distinguish from the most strongly marked specimens of chrysolite. 



The proportion formed by this mineral in the Virginia stone does not fall short of two-thirds of its entire bulk. I 

 find it also constitutes the principal ingredient in the Weston meteorites and is occasionally seen in those from Mary- 

 land. In endeavoring to ascertain if the small black grains disseminated through the Stannern meteoric stones might 

 not be this substance, I was led to conjecture from their easy fusibility before the blowpipe that they were pyroxene, a 

 mineral, from the researches of G. Rose, well ascertained to exist in aerolites. 



2. Feldspar. 



Under this name I allude to one of the most common ingredients of meteorites, although in the present specimen 

 it forms somewhat less than one-fourth of the mass. It is everywhere dispersed through the stone, filling up little 

 interstices and investing the chrysolite in thin coatings. 



Mineralogical description.— External shape, exceedingly minute grains, possessed of feeble degrees of coherence, 

 and appearing like powder to the naked eye. Structure lamellar, and visible only with a microscope. Hardness 

 such as not to allow of its impression with the point of a knife. Luster vitreous: color white, rarely with a faint tinge 

 of green; translucent. 



Chemical characters. — It was with some difficulty that pure pieces of sufficient size could be obtained for blowpipe 

 trials. A thin scale in the most powerful heat of this instrument melted down into a pearly white translucent glass 

 or enamel. With microcosmic salt it appeared to dissolve, with the greatest reluctance, into a transparent colorless 

 glass, leaving behind small skeletonlike masses of silex. With borax it dissolved with difficulty and without effer- 

 vescence into a transparent and colorless glass. 



The present mineral appears to correspond with that alluded to by Rose in the memoir before mentioned, and 

 which he found to compose nearly half of the Juvenas meteorite. He ascertained that it contained 0.60 per cent 

 of soda: a quantity so small, that he suggests unless it be a new mineral, it belongs to his species — labradorite, a sub- 

 stance better known generally under the name of labrador feldspar. Its general aspect, however, as it appears in the 

 Virginia stone, would render it more probable that it belonged to the variety albite than to the labradorite. 



It also forms a large proportion in the Maryland and Stannern aerolite, and exists in the stones of L'Aigle and Wes- 

 ton, though in the last in but very small proportions. 



3. Phosphate of Lime. 



The only remaining earthy mineral distinguishable in the Virginia stone, I take to be the above-mentioned sub- 

 stance. Its proportion in the mass is so trifling that it is scarcely perceptible without the aid of a microscope, and 

 even then only in a few points. When a fragment of the stone is broken down, however, we rarely fail to distinguish 

 a few grains which are at once recognized by their color. 



Mineralogical description. — External shape, globular and reniform. Structure, lamellar. Brittle; fracture 

 conchoidal . 



Luster, vitreous. Color, honey yellow, transparent. Hardness such as to scratch crystallized arragonite from 

 Bilin, but not asparagus stone; is scratched itself by the knife. 



Chemical characters. — Before the blowpipe upon charcoal it phosphoresces with great distinctness, and becomes 

 rounded on the edges without undergoing any perceptible ebullition and without loss of transparency. With micro- 

 cosmic salt it forms a transparent glass, at first with a tinge of yellow, but becoming colorless when cold. Compara- 

 tive experiments were made with the asparagus stone attended by similar results. 



Several small angular fragments were put into a flask, to which colorless nitric acid was added, and a slight heat 

 applied for nearly an hour, when their complete solution was effected. 



I was the more particular in my examination of this substance, not being aware that phosphate of lime had ever 

 before been detected in these stones; and I regret that the smallness of the quantity prevented me from making still 

 farther experiments, by means of which my conclusion concerning its nature might have been rendered quite certain. 



4. Meteoric Iron. 



This hitherto nearly invariable ingredient of meteoric stones is not wanting in the present instance. Its pro- 

 portion, however, is very small, as may be judged of h-om the fact that I did not find above 8 grains in breaking down 

 nearly half a pound of stone. 



Its form was for the most part that of rounded grains slightly flattened, the largest of which did not exceed a mus- 

 tard seed in size. It also existed in little hook-shaped masses, as well as in the most delicate filaments, resembling 

 the finest wire, and capable of being straightened out in single pieces to a length exceeding half an inch. Its color 

 was of a silvery whiteness, except in those instances where the fragment was situated in a large cavity, when it was 

 partially invested by rust and in some cases by a thin coating of the protosulphuret of iron. 



