8 MEMOIRS NATIONAL ACADEMY OF SCIENCES. ivol.xiv. 



position, the stones seem to be identical and there is apparently no reason for doubting the 

 authenticity of the material now under consideration. A broken siu-face is light ash gray in 

 color, thickly studded with chondrule,s, some of which are of a dark color and others very light 

 greenish when broken across. All separate readily from the ground, often in very perfect 

 spheruUtic forms. No metal is evident to the unaided eye. In thin sections under the micro- 

 scope the structure Li that of a tufaceous groimd carrying the abundant chondrules, entire and 

 fragraental, and scattered crystalline particles with the usual spi inkling of metal and metalUc 

 sulphide. It will be recalled that Siemaschko ' described this last as occmiing in pentago- 

 dodecahedral forms and, therefore, pyrite. The correctness of this has been questioned (see 

 Cohen, p. 208). The recognizable silicates are olivine and enstatite, though as often the case 

 many of the chondrules are densely crypto-crystalline and their mLneralogical natm-e inde- 

 terminable other than that they are pyroxenic. The powdered stone treated with a drop of 

 acid ammonium molybdate solution gives rise to abundant leaction for phosphorus, indicative 

 of a lime phosphate which occurs only in minute interstitial granules quite inconspicuous imless 

 specially sought under the microscope. 



The results of Dr. Whitfield's work are given below. It should be stated that particular 

 pains were taken, as usual of late, to determine the presence of the rarer elements particularly 

 tin and copper which the previous investigators had reported, and also the presence or absence 

 of nickel and cobalt in the silicate portions. 



Several grams of the finely pulverized material boiled for half an hour in distilled water 

 in a platinum vessel yielded no evidences of the presence of oldhamite. 



The mineral composition, determined by the usual methods, was foimd to be — 



Percent. 



Silicate portion (including a small amount of phosphate) 76. 274 



Troilite 6. 100 



Metallic portion 16. 800 



Ohromite (calculated) 0. 766 



Total 100. 000 



The metallic portion yielded — 



Per cent. 



Iron 92. 092 



Nickel 7. 158 



Cobalt 0. 686 



Phosphorus 0. 064 



Total 100. 000 



The silicate portion yielded — 



Per cent. 



SiO, 44.438 



AljO 0.226 



CrA => 0. 550 



P2O5 0. 503 



FeO 13. 675 



MnO 0. 376 



CaO 1. 505 



MgO 27. 204 



NiO 0. 678 



OoO 0, 066 



Na,0 1.186 



K,0 0.222 



SO, 0. 371 



Total 100. 000 



' Tschermak's Min. u. petro. Mitt, vol. 11, 1890, p. op. ' Equals 0.766 cUromite. 



