METEORITES OF NORTH AMERICA. 67 



If this result be reduced to 90.75 per cent and the constituents of the decomposed portion be added, we have — 



Silicic acid 57. 52 



Alumina 2. 72 



Iron oxide 1. 25 



Manganese protoxide 20 



Magnesia 34. 80 



Lime 66 



Soda 1. 14 



Potash 70 



Loss by heating 80 



99.79 



Next arises the question, Is this one compound or a mixture of several? I conjecture the latter, because the 

 alumina points to the presence of a small amount of silicate, and my own experiments deviate so widely from the 

 former investigation, according to which the nearly 70 per cent of acid seemed strange in every case. 



The stone affords no opportunity for mechanical separation, however, since the white mass shows no other vari- 

 ation than that of greater compactness in certain places. I washed it and examined the lightest as well as the heaviest 

 for essential constituents, not at all in the hope of effecting a division of the constituents thereby, but merely with 

 the object of determining definitely the similar or dissimilar composition of both portions. 



I obtained the following: 



Silicic acid 58. 74 57. 12 



Alumina 6. 16 2. 13 



Oxide of iron 1.82 2.71 



Magnesia 29. 78 36. 71 



Lime 1. 70 1. 48 



Loss (alkali) 1. 80 



100. 00 100. 15 



Thus, in fact, both are different, the alumina and alkali bearing silicate being especially noticeable in the lighter 

 portions. 



After this it appears entirely needless, for the present, to speculate concerning the nature of this compound. 

 But I do not omit to emphasize the fact that the chladnite and the supposed magnesia trisilicate appear as notable 

 exceptions, and further call attention to the fact that the composition of the groundmass of the stone from Bishop- 

 ville, as determined by me, shows a great similarity with that of the substance investigated by Stromeyer, if the iron 

 protoxide of the latter be converted into its equivalent magnesia. 



Rose 6 described the meteorite as follows : 



The group Chladnite contains only one meteorite. This fell at Bishopville, South Carolina, in March, 1843. 

 There fell only one stone weighing about 13 pounds, which was acquired after its fall by Professor Shepard, to whom we 

 owe the first description and analysis. Afterwards Sartorius and Rammelsberg made investigations of it. The Berlin 

 collection possesses a large piece weighing 4.86 ounces and smaller ones. The stone has very slight cohesion and 

 falls in pieces at the slightest pressure. It is in general of a porphyritic granular structure. In a gray, spotted with 

 white, finely granular groundmass there occur, besides some smaller ingredients of lesser importance, only snow-white 

 crystals of different sizes in great quantity. The largest crystal of the piece in the Berlin Museum shows on the surface 

 of the stone a section of rectangular shape with truncated angles. It is 0.5 inch long and somewhat less broad. 

 Another shows the shape of a symmetrical hexagon with two parallel sides over 0.5 inch long and a little less than 0.25 

 inch broad. The first two crystals are penetrated by parallel cleavage faces which are, however, not complete but 

 broken by intervening fracture. The fractured surface has a pearly luster and is traversed by dull striae parallel to 

 the longer side. The origin of these I do not know, but one sees them on sections of other crystals as well as the 

 bright cleavage surfaces in another direction. There occur also round white grains about the size of a pea, which are, 

 however, not all round, for when taken out they leave uneven hollows in the stone. They are transparent with 

 vitreous luster. When one takes the crystals or grains out of the stone they fall into little pieces on account of being 

 penetrated in different directions with many straight and curving clefts. It is probable that the grains are different 

 from the crystals, and probably also that these are distinguished by the bright and striated cleavage surfaces. Shep- 

 ard mentioned the round grains and separated them from the crystals. He regarded the former as anorthite, without, 

 however, further testing than with the blowpipe. The crystals he regarded a new mineral, to which he gave the 

 name chladnite and which he has allowed me to change to shepardite. Of the form of these shepardites he made no 

 record, although he mentions crystals nearly an inch in diameter. In general they have, according to him, the appear- 

 ance of common forms of feldspar and calcite. The original form was a double prism. By cleavage, which takes 

 place easily, angles of 120° and 60° are observed. Sartorius also speaks of the form of these crystals and compares it 

 with that of wollastonite without giving further angles. He only mentions the small microscopic crystals and does 

 not state how these occur. The hardness of the shepardite is, according to his observation, that of feldspar. The 



