310 THE SCIENTIFIC PAPERS OP 



experimentally at the details of the process, and several applica- 

 tions had been made of it at other works, but they were hardly 

 sufficiently advanced in practice to give any working results. 

 With regard to the President's observation concerning his ore 

 process, he must admit that it was a legitimate criticism, namely, 

 whether in the rotary furnace, carbonic acid could be kept away 

 from the metal as it was forming. He (Dr. Siemens) still main- 

 tained the argument he used last year, that the carbonic acid 

 remained separate from the ore, and that in this respect he had an 

 advantage over the blast furnace. Of course, there was no abso- 

 lute separation of the carbonic acid formed from the ore, and 

 practice alone could show whether the reduced metal was effectu- 

 ally protected against re-oxidation under these circumstances. 

 The results he had obtained showed that they could get about 80 

 per cent, of the iron from the ore, which did not seem a good 

 result as contrasted with the blast furnace practice, but if they 

 compared it with the working of a blast furnace and the subse- 

 quent puddling furnace combined, it was by no means a bad 

 result, and he (Dr. Siemens) claimed to be judged by that standard. 

 His advantage consisted, however, chiefly in economy of fuel. He 

 was glad that the President had alluded to a project which had 

 found vent in the public press, of using chalk instead of coal. 

 He thought that, on the whole, the President had dealt too 

 leniently with that project. They should remember that chalk 

 was the result of a double combustion a combustion of calcium 

 and a combustion of carbon both combustions being perfect in 

 themselves, leading to a further combustion of the two combined 

 together, and, therefore, if the originator of that scheme had 

 looked all the world over, he could not have found a more 

 thorough cinder. 



