METEORITES OF NORTH AMERICA. 



253 



meteorite. This ferruginous substance has penetrated all the crevices of the mass, being found in the interior of even 

 the largest mineral grains, is seen in patches throughout all the sections, and is what gives the brown color to the mass. 



A careful search revealed no grains of troilite, though the chemical analysis shows that about 5 per cent was prob- 

 ably present originally. It has possibly been entirely decomposed. 



For the chemical analysis 25.2 grams were taken, of as fresh material as was available, with no crust attached. 

 An attempt was first made on 13 grams to separate the nickel-iron by means of an electromagnet. This proved to be 

 a matter of great difficulty, on account of the very dense and compact texture, and after two days had been spent in 

 successive separations under alcohol, and after analyses of the products had been partially completed, this method 

 was abandoned . 



Eggertz's iodine method was finally employed and proved fairly satisfactory. 



The results of the several analyses are given below, the total analysis being calculated from the data furnished by 

 the others. Part of the Cr 2 3 was determined as chromite — this being assumed to have the simple composition FeC'r 2 4 ; 

 the rest was precipitated as PbCr0 4 . H 2 was determined as such in the total meteorite by Penfield's method, and 

 referred to the soluble portion. S and P 2 O s were likewise determined in the total meteorite. The separation of sol- 

 uble and insoluble silicates was effected in the residue from the solution of the nickel iron by digestion on the water 

 bath for three hours with dilute HC1 (1 : 5), and subsequent treatment with dilute KHO solution. The extra oxygen 

 of the soluble portion, the total iron being determined as PeO, is that belonging to the ferric oxide of the limonite. 

 It was estimated by calculating the amounts of olivine, augite, and diopside present, and deducting the amount of 

 FeO belonging to them from the total FeO. 



The specific gravity was found to be 3.466 at 15.5° C, taken with the balance, on a mass of 11 grams. The first 

 approximate composition is: 



Nickel iron 4. 25 



Troilite 5. 16 



Silicates 54.47 



Chromite 0. 87 



Soluble. 



Insoluble. 



100. 00 



The analysis of the nickel iron yielded: 



Fe 89. 67 



Ni 10. 01 



Co 0.32 



Cu undt. 



100. 00 



The analyses of the soluble and insoluble portions, together with the calculated total composition, are as follows: 



Soluble in HC1. 



Si0 2 21. 34 



TiO 2 



A1 2 3 0.27 



FeO 41.38 



Fe 



NiO 2.67 



Ni : 



CoO trace 



Co 



MnO 



MgO 22.86 



CaO 0.46 



Na-jO undt. 



K 2 undt. 



H 2 5.08 



PA 0.62 



S 3.15 



Extra 2. 88 



Less 0=S. 



100. 71 

 . 1.57 



99.14 



99.40 



It is evident that the soluble portion is made up largely of olivine, with troilite and limonite, and small quantities 

 of pyroxene and oxide of nickel; while the insoluble is chiefly bronzite, with accessory chromite, feldspar, and augite. 



