376 MEMOIRS NATIONAL ACADEMY OF SCIENCES, VOL. XIII. 



Analysis. — From the foregoing trials I inferred that the meteoric iron was alloyed with nickel only, and, accord- 

 ingly, I endeavored to form an estimate of the relative proportions of these metals by determining the weight of 

 peroxide of iron afforded by a certain quantity of the compound. For this purpose, 3 grams of the mineral were dis- 

 solved as usual in nitro-muriatic acid. The solution was perfect, with the exception of 0.05 gram earthy matter, which 

 remained undissolved. Ammonia was added, and the liquid heated for a few moments. The precipitate, separated, 

 washed, dried, and ignited, amounted to 3.9G grams, equal to 2.77 metallic iron; thuB, leaving by deduction, 0.18 

 gram nickel in 2.95 grams of the alloy, or per 100 — 



Iron 93.90 



Nickel 6. 10 



100. 00 

 5. Protosulphuret of iron. 



This is the only remaining constituent of the Virginia aerolite I have to describe. Although everywhere dis- 

 seminated through the stone, and almost completely lining its cavities in little grains and semifused crystals, yet such 

 is their minuteness that it scarcely forms a more considerable ingredient than the meteoric iron. 



Mineralogical description. — Form: Distinct crystals, of which I obtained three, of sufficient dimensions to enable 

 me, with the aid of a magnifier, to ascertain their shape, and to determine the value of their principal angles by the 

 reflective goniometer. The most perfect of the three, offered only the sides M. M', and their four adjoining pyramidal 

 planes c, c, c', and c', with the truncature a, as seen in the annexed diagram; the other planes of the figure were 

 inferred from the relation of these, the regular six-sided prism being known to be the fundamental form of the species. 



M, on M' 120° 



— on c 153. 20' 



c, on a 117.30' 



Structure: Cleavage imperfect. Brittle. Luster steel-like and splendent. Color, steel-gray upon the crystalline 

 faces; copper yellow on fractured surfaces. Extremely subject to tarnish, of which the steel blue and red form the 

 most frequent colors. 



Hardness: Not impressible by steel. 



Chemical characters. — Before the blowpipe, on charcoal, it enters into immediate fusion, emitting at the same 

 time sulphurous fumes; the globule formed assumes a deep red color while hot, but turns to a dull black, and becomes 

 strongly magnetic on cooling. 



To 0.4 gram in powder was added hydrochloric acid. The flask was fitted with a tube dipping into a solution of 

 acetate of lead. An action immediately commenced, on slightly warming the fluid, and a copious precipitate of sul- 

 phuret of lead ensued. 



The difference in magnetic properties between the meteoric protosulphuret of iron and the same mineral belong- 

 ing to our globe, led M. Pvose to examine the former for nickel; conceiving that as the sulphuret of nickel of Johann 

 Georgenstadt is not magnetic, a portion of this metal combined with our mineral, might perhaps be the cause of its 

 not affecting the needle. He was unable, however, to detect the smallest trace of nickel in the pyrites of the Stan- 

 nern stone. Nevertheless, as the common magnetic pyrites possesses but feeble and very variable degrees of magne- 

 tism, the slight discrepancy here observed between the two substances in question does not interfere in any force 

 with the idea of their specific agreement. 



A further account of the apatite was given by Shepard, 4 as follows: 



M. Rumler, in a recent number of Poggendorff, in enumerating certain ingredients in meteorites, after the men- 

 tion of phosphoric acid, adds, "For Shepard's discovery of this acid in the meteoric stone of Richmond, is still 

 doubtful (denn Shepard's Entdeckung dieser Saure in Meteorsteine von Richmond ist noch zweifelhaft)." Although this 

 observation occasioned in me no surprise, since I had stated at the conclusion of my remarks on the mineral, my 

 regret "that the smallness of the quantity prevented me from making still further experiments by means of which 

 my conclusion concerning its nature might have been rendered certain," still it determined me to make new trials for 

 placing the subject, if possible, beyond dispute. 



Through the kindness of Professor Silliman, who possesses nearly the whole of the Richmond stone, I was per- 

 mitted to detach a fresh fragment which brought into view several points of the yellow mineral in question. The 

 most perfect of these, having the size of half of a pin's head, was crushed to powder on a small piece of clean platinum 

 foil, previously fitted to the bottom of an agate mortar. The foil with the crushed mineral thereon was then shaped 

 into a little cup, and a freshly cut piece of potassium pressed into it, so as to be in immediate contact with the 

 powder. The platinum cup and its contents were then forced to the bottom of the test tube (0.25 inch in diameter 

 and 2.5 inches long); and after heating the tube in contact with a live coal, until a slight flash of light was witnessed 

 in the platinum cup, a few drops of water were let fall into the tube. On holding the open end of the tube beneath 

 the nose, a distinct odor of phosphuretted hydrogen was recognized. A few drops of dilute nitric acid were subse- 

 quently added ; and after digestion for a few moments and neutralization by ammonia, oxalate of ammonia threw down 

 an evident precipitate. 



The foregoing experiment clearly establishes the presence of phosphoric acid in the mineral; and the precipitate 

 with oxalate of ammonia, taken with all the circumstances detailed in my mineralogical account of the substance, 

 leave scarcely a doubt of its being combined with lime, in the form of phosphate of lime. 



