in augmentmg the quantity of Phosphorus in Fic/-iron. 425 



amongst tlie constituents in the various analj^ses of blast-furnace 

 slags which he has described in his work. 



From experiments made by assaying pure hfematite with vari- 

 able per-centages of phosphate of lime* and suitable proportions 

 of flux and charcoal, we have, by analysing the buttons of metal 

 and slags obtained, taking care to select those only in which the 

 operation was perfect, that is to say, in which a colourless slag 

 and graphitous button were produced, also corroborated Ber- 

 thier's results, as will be apparent from the following table : — 



In the assay of ores, and also of scoriae from forge- and mill- 

 furnaces, which contain a large amount of phosphoric acid, 

 results widely diflFerent to the foregoing were arrived at. The fol- 

 lowing, selected from a great number of experiments, are marked 

 illustrations of this : — 



The time occupied in performing the assays, and the furnace 

 conditions under which they were conducted, were about the 

 same in all cases. Where flux was employed, it consisted of two 

 parts of clay-shale and one part of lime. 



It is necessary to state, that the phosphoric acid in the ores 

 above cited was in combination with lime. In the cinders it 

 existed as phosjihate of iron. 



In experiments Nos. 1 and 2, it will be seen that the quantity 

 of phosphorus found agrees pretty well with the theoretical 



* The amount of phosphoric acid in the phosphate of lime was previously 

 determined. 



Phil. Mag, S. 4. Vol. 10. No. 68. Dec, 1854. 2 F 



