METEORITES OF NORTH AMERICA. 451 



Some crystals are long and thin, others short and thick. They are always doubly terminated and show no trace 

 of erosion. Measurement under the microscope gives: 



(101) (101)=114° 30', the calculated value being 114° 43'. 



Cleavage like that of rutile could not be observed, and in one case there is excellent conchoidal fracture on one edge 

 of the prism. The crystals are always light reddish, quite clear, and pure. They show a high index of refraction, 

 with high interference colors, and the axis of the smallest elasticity is the principal axis. They thus agree com- 

 pletely with the microscopic zircons of terrestrial rocks. Single black crystalline sharply-bounded grains in the resi- 

 due are perhaps chromite, or cliftonite— black plates, perhaps graphite. The olivine and anorthite which dissolve 

 in acid should also be recognized as constituents of the sandy substance. In all the transparent constituents of the 

 residue, but especially in the quartz, occur darkly bordered gas pores and small inclusions having a mean refraction 

 between that of glass and a fluid. These always contain spherical bubbles, generally single but occasionally double, 

 triple, or quadruple. Neither by shaking nor warming the Canada balsam to 32° C. did the position or size of these 

 bubbles change. They belong, therefore, to the glass inclusions which are very abundant in meteorites, but which 

 have not yet been known to contain a fluid inclusion. 



Finally, in all the constituents of the residue, except in the supposed orthoclase and zircon, occur doubly refract- 

 ing needles resembling in appearance the apatite needles of terrestrial rocks. It is true that apatite has not yet been 

 proven to exist in meteorites, although Rammelsberg found 0.28 per cent phosphoric acid in the eukrite of Juvinas, 

 which would correspond to 0.60 per cent of apatite. Since this eukrite contained almost no nickel iron which could 

 unite with phosphorus, the occurrence of apatite in the meteorite seems probable. The form and mineral content of 

 the residue described above leaves no doubt that it does not represent foreign matter but an original constituent of 

 the meteoric iron. Of the substances found by Cohen and Weinschenk in Toluca, I was unable to find the following: 

 Colorless transparent glass polarizing weakly; a cordieritelike mineral; dark-brown isotropic grains with strong luster; 

 and transparent isotropic glass splinters. The essential differences between my observations and theirs lie, of course, 

 in their failure to observe feldspar, zircon, and apatite; but the microlites which they describe as No. 1 may corre- 

 spond to my apatite, and those which they mention as No. 2 to my orthoclase. On account of these differences, I 

 dissolved a large quantity of the foliated rust which had accumulated from the crust by years in the museum, but 

 obtained therefrom exactly the same solution and the same residue as from the sandy portions on the surface. In 

 order to guard against the possibility that these portions of the crust had not formed in the natural position and had 

 been mixed with sand, I dissolved in hydrochloric acid a piece of the Toluca iron from Krantz's collection weighing 

 82 grams, which was compact and solid, nearly surrounded by limonite but regularly penetrated by numerous taenite 

 lamellae. After about one-half of this had been dissolved the portion remaining showed many thin almost parallel 

 streaks of clear, gray, granular, altered silicates, separated by silica which dissolved in caustic soda. These streaks 

 had the shape and composition of the stony portion of the surface. In the solution were found again magnesia, iron, 

 clay, and lime, indicating predominant olivine and some anorthite. The residue showed under the microscope the 

 same contents as in the two other cases. Similar streaks were noted by Reichenbach in the Toluca iron. These he 

 regarded as olivine and described and figured them. Similarly distributed silicates have also been observed in other 

 meteoric irons. There thus exists no doubt that quartz and zircon and the other substances mentioned occur as orig- 

 inal constituents of the Toluca iron, and it may be possible in time and by solution of a large quantity of the gradually 

 accumulating rusts of the Toluca meteorite in the museum to establish by chemical analyses the existence of zircon 

 and the supposed orthoclase and apatite. 



Brezina, 36 in 1895, gave further observations on Toluca as follows: 



To Toluca doubtless belong the irons from Amates, Ameca-Ameca, and Cuernavaca, which are placed here by 

 Fletcher. Here also belong, according to a brief missive from Professor Klein, of Berlin, the Berlin museum speci- 

 mens of Sierra Blanca, near Jiminez and Villa Neuva de Huejuquillo, found in 1784. In all probability, too, the iron 

 from Rincon de Caparrosa belongs to Toluca, as well as that of Chilpanzingo, State of Guerrero. Castillo supposes that 

 this lump of meteoric iron, originally weighing 341 grams, fell to earth as the result of the breaking up of a piece of 

 chalcopyrite-bearing talc schist from Caparrosa. At the Paris Exposition of 1889, I examined this iron, as well as the 

 mother stone from which it is said to have fallen out. The iron did not fit the hole exactly, but very nearly. While 

 the iron is covered with a limonitish weathering crust and has suffered a comparatively widespread deformation and 

 evening off of the exterior, through weathering, the surface of the hole in the mother stone shows no signs of this rust- 

 ing-off process, which must have taken place inside of the cavity. From this fact it follows that the lump of iron could 

 not well have come from the Caparrosa schist. 



Apparently in connection with the schist formation a piece of stone fell to earth and a hitherto unnoticed lump 

 of meteoric iron was picked up at that point, as many such from the Toluca find may have lain around in the collec- 

 tion of the mining school. The etching of a section of this lump of meteoric iron moreover, shows complete agree- 

 ment with that of Toluca. Further, the small piece of the meteorite from Tule, Balleza, Chihuahua, found in the 

 School of Mines, in Mexico, may belong to Toluca. 



Of the specimens in the Vienna collection, the oldest one designated as Toluca, which is stated to have been 

 acquired from Bergemann, in Berlin in 1810, certainly belongs to another locality. It has almost fine lamellse and 

 is throughout lustrous, with well-developed fields containing only dark plessite; it has also abundant taenite. This 

 iron may belong to Morito, Pila, or Descubridora; the marked deformation, apparently due to dismemberment, makes 

 a definite determination difficult. The study of numerous pieces of the Toluca iron gives many new phenomena; 



