THE METEORIC BASALTS. — GABBRO. 201 



liaiit than terrestrial augite, and resernljles olivine. All the transparent minerals of the 

 section are clearer, and lighter-colored than their mundane representatives, and hence tend 

 to sliovv in polarized light clearer and more brilliant colors. The augite is not, liowever, 

 quite so water-clear as the enstatite, but has a very faint tinge of yellowish-green. The 

 ferruginous inclusions are the same in this as in the enstatite. 



The determination of the olivine is more doubtful, since it is seen only in small irreg- 

 ular grains and masses, which hold the same relation to the other minerals that the (divine 

 of terrestrial gabbros usiially does to its associated minerals. From this, and the fact that 

 it optically has the cliaracters of olivine, it is here assigned to that species. 



From the description of the mineral constituents of this meteorite, it would seem that, 

 regarding the presence of the feldspar, Messrs. Shepard and Waltershausen were correct, 

 wliile Eammelsberg was not. It shows the inability of the ablest mineralogical chemists 

 to draw correct conclusions regarding the mineral constituents even of an xnialtered rock. 

 The trouble appears to reside in the instrument used — a defect in the method. 



Chladnite ought no longer to be regarded as enstatite of the purest kind, as stated 

 in most mineralogies, but rather as a mineral aggregate of which enstatite, feldspar, 

 and augite are the principal constituents. While these observations gave an approximate 

 solution of the Bishopville meteorite puzzle of twenty-seven years standing, it would 

 be well if some one having larger amounts of this meteorite could make a chemical 

 analysis of it as a wliole, and also analyze the minerals by the modern microscopic, 

 specific-gravity, chemical method.* 



This stone, from the above observations, is, in its minerg,logical composition, structure, 

 bubble-bearing glass inclusions, and microlites, like a terrestrial eruptive rock, and it is 

 presumable that it had a similar origin. 



Tliere are many who hold that the terrestrial eruptives are produced by the aqueo- 

 igneous solution of chemical precipitates from the primeval ocean or thermal springs, or 

 from sediments buried under the ruins of the earth's crust. Would it not, then, be in 

 order for these scientists to explain the formation of this meteorite in the same way ? 

 'Now if this bod}^ was thrown from the sun or a similar globe, by eruptive agencies, 

 would it not tlien be proper for these writers to speculate how this sun commenced 

 with a cold, inert surface, and a solid interior ; and how, later, by its being blanketed 

 by its own detritus, it had been raised to its present intensely heated condition ? — 

 a speculation which is in entire accord with methods formerly advocated by ardent 

 Wernerians to account for the heated condition of the earth. 



Since the publication of the preceding description of this meteorite, Tschermak 

 has published independently another description. He recognized the prefc-nce of 

 enstatite, plagioclase, and pyrrhotite.f 



Manegmim, India. 



The Manegaum meteorite was described by Maskelyne in 1863, as composed of a 

 probable olivine and an opaque white or yellowish-white mineral. The latter occurs 

 as a flocculent network, in round spherules, in fragments, and along the laminas of the 

 crystals of other minerals. Some pyrrhotite and chromite (?) were observed. :j: 



In 1870, Maskelyne determined the supposed olivine to be enstatite, to which he 



* Am. Jour. Sci., 1883 (3), xxvi. 32-36, 248. 



t Die mikros. Bescli. der Meteoriten, 1883, i. 9, 10; Sitz. Wien. Akad., 1883, Ixxxviii. (1), 363-365. 



X Phil. Mag., 1863 (4), xxvi. 135-139. 



26 



