D. CHEMISTRY AND METALLURGY. 217 



TEMPERATURES IN PNEUMATIC STEEL MAKING. 



According to Kraus, the flame enters the Siemens-Martin 

 furnace at a temperature of about 3000 C. (over 5400 Fahr.), 

 and the furnace itself acquires a temperature of 1800 C. 

 (3243 Fahr.). These figures may be taken as the maximum. 

 In the Bessemer converter a higher temperature is possi- 

 ble say 2500 C. (4500 Fahr.); since the carbonic oxide 

 formed by the combustion of the carbon of the cast iron is 

 not so readily dissociated at high temperatures as carbonic 

 acid, and the burning silicon remains in the metal bath as 

 silicic acid. The small neck of the converter aids the accu- 

 mulation of heat by effecting an increase of pressure, which, 

 in turn, retards dissociation. 



ALUMINIUM IN PLANTS. 



It has been known for some time that while the metal 

 aluminium is found in a few of the cryptogamous plants, it 

 is not to be detected among flowering ones. Professor A. H. 

 Church has been recently investigating this subject, and pub- 

 lishes the result in the Chemical News. So far he has found 

 this element in four species, and in the following proportions : 



Percentage 100 parts of Ash 



of Ash in contain 



Dry Plant. 



-^v- 



~\ 



Silica. Alumina. 



Lycopodium alpinnm 3.68 10. 24 33. 50 



L. clavatum 2.80 6.40 15.24 



L. selago 3.20 2.53 7.29 



Selaginella Martensii 11.66 41.03 0.26 



1 A, September 18, 1874, 138. 



REDUCING RICH IRON ORES. 



Dupuy's direct process is described as a new method of 

 reducing rich iron ore from its oxide to cakes of compara- 

 tively compact metal at one heat. These are then withdrawn, 

 and at the same heat forged for wrought iron, while for steel 

 purposes they are thrown, without forging, into the molten 

 bath of the Siemens furnace, or cut up and melted in pots. 

 The ore is used as ordinarily prepared for the common forge 

 fire. It is mingled with the proportion of pulverized char- 

 coal found requisite for complete reduction, which is but a 



K 



