Sffi WILLIAM SIEMENS, F.R.S. 345 



a portion of the cinder again in succeeding charges, but the pro- 

 lonion of cinder that may be so used with impunity, depends 

 upou the amount of phosphorus, sulphur, and alumina contained 

 in the ore.* The coal used in the producers amounted to 2 tons 

 per ton of hammered blooms produced, and in pricing the mate- 

 rials used and labour engaged upon the work, the table prepared 

 by the manager at the Works gives 3 8s. as the cost per ton 

 of hammered blooms. To this amount must be added repairs 

 and general expenses, and the cost of rolling the hammered blooms 

 into bars, which in the case of Towcester practice are very heavy, 

 but of which an experienced ironmaster would form his own esti- 

 mate. The cost of working the metal in the hollow fires is also 

 not included, and this may be taken to add from 25s. to 80s. to 

 the ton. The refined iron so produced will, therefore, cost from 

 5 5s. to 5 10s. per ton. 



Tables II. and III. give the analyses of irons produced from 

 various descriptions of ores, and Tables IV. and V. give Kirkaldy's 

 tests of the mechanical properties of the iron ; but it should be 

 under-stood that these tests were taken with a view to ascertain 

 the influence of different methods of manipulation rather than to 

 show high results. Only a small proportion of the samples had 

 been subjected to the refinery process, and the variable percentage 

 of phosphorus may be taken really as indicative of the extent to 

 which the cinder had been removed from the metal. 



Table VI. gives the analyses of slags produced in the process. 

 These are no doubt rich in iron, but it must be remembered that 

 in the case of comparatively pure ore they can be used almost 

 entirely in succeeding charges, and that in the case of ores con- 

 taining much sulphur and phosphorus they are the recipients of 

 those impurities in the same way as the puddling cinder carries 

 off the same impurities in the puddling furnace and thus serve a 

 useful end. 



If rich ores, such as hematites, are available, it is more advan- 

 tageous to use a stationary furnace, and to modify the process as 

 follows. 



* Since this paper was prepared, further experience has shown the possibility 

 of obtaining greater yields of iron from the ores employed, and of making, at the 

 same time, a greater number of charges per 24 hours ; some of these results are 

 recorded in Tables VII. and VIII., which may be considered as appendices to this 

 paper. 



