METEORITES OF NORTH AMERICA. 351 



by a treatment of the powdered stone with hydrochloric acid to be present, is nevertheless not to be recognized even 

 with a glass. Among the other constituents of the stone I noticed a single crystal (apparently do.decahedral) of a hard 

 red earthy mineral, closely resembling the substance I called garnet in the Nobleboro (Maine) meteoric stone. 



The stone breaks with rather more than the usual facility of meteoric stones. The specific gravity of fragments 

 =3.23. The nickeliferous iron separated by the magnet amounted to 2.5 per cent. The stone was then finely powdered 

 and on digestion with strong hydrochloric acid readily suffered decomposition in the feldspathic part of its constitution 

 with the separation of silicic acid. The solution afforded the following constituents in the ratios annexed: 



Alumina 13. 00 



Lime 4. 00 



Protoxyd of iron 1. 80 



Magnesia 50 



which, coupled with the concurring mineralogical and blowpipe evidence of the character of the leading constituent 

 of the stone, leaves no doubt of its being true anorthite. The pyroxene, chladnite, and olivine afforded each the usual 

 blowpipe proofs of then- agreement with those species, respectively. 



The following may be taken as a tolerably close approximation of the mineral constitution of the Petersburg stone: 



Anorthite 82.0 



Chladnite 9. 



Olivine 5.0 



Pyroxene 1.0 



Nickeliferous iron 2. 5 



Chromite and pyrites 0. 5 



100.0 



Smith 3 four years later published a very similar account of the meteorite, giving practically 

 no new information. 



Rose 4 classed the meteorite with Juvenas, Stannern, and Jonzac as a eukrite and described 

 it as follows : 



The eukrite of Petersburg is at first glance a very strange looking eukrite. The mineralogical museum possesses two 

 not very large pieces which were obtained from Shepard by Dr. Bondi. The larger part of the stone consists, so far as 

 these show, of a grayish-white, fine-grained, friable mass which, examined with a lens, is seen to be a fine mixture of 

 small brown and snow-white grains containing single larger greenish-yellow grains of olivine, also small grains of troilite 

 and little flecks of rust which come from the nickel iron, of which one can draw from the powder with a magnet a not 

 inconsiderable quantity for a eukrite. In this general mass lie portions a half inch in diameter of a coarser mixture of 

 brown and white grains which are plainly augite and anorthite and are very similar to those seen in Juvenas and Stan- 

 nern. Also there are found in the gray mass angular black particles sharply separated from their surroundings and 

 having a flat dull fracture. This can not be recognized with the lens as a mixture but it may be, since before the blow- 

 pipe it, like the gray matter, melts on the edges to a black glass which is weakly attracted by the magnet, and which, 

 in salt of phosphorus, leaves a skeleton of silica and a glass colored weakly green by iron. Externally the meteorite has 

 a black shining crust like that of Juvenas and Stannem. The eukrite of Petersburg thus corresponds with other 

 eukrites and differs from them only in the addition of olivine and a somewhat greater quantity of nickel iron. 



Reichenbach 5 gave the following description of the occurrence of what he believed to be 

 pure sulphur in the meteorite: 



A specimen of the Petersburg meteorite, 2 ounces in weight, exhibited just under the crust a pale yellow inclusion 

 of the size of a transverse section of a lentil. It is of a scaly crystalline structure upon the fracture, pure sulphur-yellow 

 in color, easily friable under the knife, and crushes under the teeth with the peculiarity of sulphur. I was not in a 

 position to push the analysis further but hazard the guess that the sulphur-yellow substance can be nothing else but 

 pure sulphur. 



Rammelsberg 6 gives the following analysis of Petersburg: "Augite 68.6 per cent, eukrite 

 (anorthite) 30.0 per cent, magnetic pyrites 0.6 per cent." The composition of these is as 



follows : 



Anorthite (eutritc). 



SiO 2 A1 2 3 CaO Na 2 O 



12.90 11.05 5.28 0.83 = 30.06 



42.91 36.76 17.56 2.77 =100 



Augite. 



Si0 2 FeO MgO CaO 



36.31 20.41 8.13 3.73 = 68.58 



52.94 29.76 11.86 5.44 =100 



