Analysis of Iron Ore. 33 



It is necessary to remark that this specimen, among these 

 rhomhoidal grains, contained some grains of carbonate of 

 lime, which were white^ and very distinct from those of the 

 spathic iron : there were also some veins and crystals of 

 quartz and some atoms of pyrites in the abpve specimen. 



No. 3. Spathic Iron of Allevard, Department of Is ere. 



This specimen \va9 transmitted to me by professor Has- 

 Benfratz. It very much resembled Nq. 2. in colour, lustre, 

 and transparency ; it is well crystallized, very homogeneous, 

 and in good preservation. It is easily divided into rhom- 

 boids, the plates of which, when they are slender, are per- 

 fectly diaphanous. 



Analysis. 



(A) I first endeavoured to ascertain if the three speci- 

 mens of spathic iron contained any lime. In order that I 

 might not confound that which might be in the matrix 

 with that which formed part of the crystals, I carefully se- 

 parated the particles which differed in appearance from the 

 dominant part ; I also took care only to employ crystalline 

 fragments. After having reduced them into impalpable 

 powder, I introduced five grammes of each of the speci- 

 mens into three glass phials, numbered. I added a little di- 

 stilled water in order to dilute the powder and to diminish 

 the action of the sulphuric acid, which I poured in by de- 

 grees to complete saturation; As in the cold the action was 

 almost nothing, the three phiak were exposed to a heat 

 scarcely capable of bringing the mixture to the boiling 

 point J the combination of the sulphuric acid then slowly 

 commenced ; it was accompanied with the effervescence 

 usual ih the disengagement of carbonic acid gas Until the 

 solution was complete. No. L yielded no residue; No. II. 

 yielded what scarcely weighed 0-01 gramm. ; that of No. III. 

 the only one which could be ascertained, weighed 0*04 

 gramm. It was nothing else than a little silex, which had 

 probably escaped observation from being in the crystal*. 

 The solution was preserved a long time, and remained co- 

 lourless, and deposited nothing. Had these substances con- 



Vol. 25. No. 97. June l&tfo*. C taincd 



