CHEMICAL SCIENCE. 197 



Among other curious results arrived at by MM. Deville and Debray, we 

 may mention the discovery of another condition of osmium, differing; from 

 that obtained by the method of Berzelius. In its new form, so far from 

 being oxidizable at common temperatures, it may be heated to the fusing 

 point of zinc without oxidizing or yielding odors of osmic acid. As pre- 

 pared by the old method, it was spongy with a sp. g. of 7; by the new one 

 its sp. g. is 21.3, or even 21.4. The experimenters could not succeed in fusing 

 it. Palladium likewise behaves in a singular manner. " It is soluble in zinc, 

 but docs not combine with it; for when the alloy is treated with hydro- 

 chloric acid, only palladium remains. With tin it is otherwise. If palladium 

 with six times its weight of tin be fused at a red heat, and the alloy when 

 cold be treated with muriatic acid, a brilliant crystalline compound remains, 

 having a composition of Pds Sn2." With silver and copper it yields simi- 

 lar compounds. 



MAGNUS ON THE PROPERTIES OF IRON IN POWDER. 



Metallic iron in a state of very fine division has for some years been used 

 in medical practice. It is thus obtained when the oxide of iron is reduced by 

 hydrogen. When well prepared, this form of iron is so combustible as to 

 take fire on exposure to air, burning with scintillation. A manufactory has 

 lately been established in the Tyrol for making iron-powder of very con- 

 siderable fineness, although the process is mechanical, consisting in using 

 very fine files. Its therapeutic properties have not yet been decided. It 

 docs not burn spontaneously in air, although it is extremely combustible, as 

 the following experiment by Magnus clearly demonstrates. Thus, when a 

 burning body is approached to these Tyrolean filings they do not inflame 

 unless they are previously suspended from the poles of a magnet. This ex- 

 periment is easily repeated, and is interesting in a lecture. If a magnet be 

 thus armed with these fine filings, and a flame applied, a combustion begins 

 which spreads rapidly, and if the magnet is jarred a shower of burning 

 particles fall through the air. 







ALLOTROPIC CONDITION OF IRON. 



M. Keshner has recently shown that by the prolonged boiling of a basic 

 nitrate of iron its condition is changed, so that a precipitate obtained with 

 sulphate of soda, and dried in a current of air upon porcelain, is insoluble in 

 concentrated acids, but very soluble in water, the solution being turbid by 

 reflected and clear by transmitted light. In this state the iron does not 

 exhibit the customary reactions with ferrocyanides and sulphocyanides. He 

 also found that light, as well as heat, was capable of producing this allotropic 

 state of the iron salts. 



KRUPP'S STEEL WORKS AT ESSEN, GERMANY. 



The cast-steel manufactory of F. Krupp, of Essen, is the largest steel 

 manufactory in the world. It is situated on the skirts of the town, in the 

 midst of the coal mines, and covers, with its buildings and yards, a space 

 sixteen hundred by eighteen hundred feet; fifteen large chimneys tower 

 above it, and an incredible number of small ones are continually in use. A 

 cloud of smoke hangs all the week over the vicinity, and only disappears 

 with the quiet of Sunday. About fifteen hundred men are employed iii the 



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