44 
they supposed that the atmosphere contained 20 parts of oxy- 
gen with 80 of nitrogen, the latter having no action whatever, 
as was supposed, in the converting process, would pass off 
without serving any useful purpose in the smelting of ore ; but 
if it underwent decomposition, by its oxygen being so much 
reduced by the carbonizing of the coal, and the hydrogen 
became converted into flame, he did not see the proposition so 
clearly. Mr. Babbage, who had given his opinion on the 
subject, thought a process might be adopted so as to liquify 
the oxygen. As, however, he was speaking in the presence 
of several iron masters, and as he had great deference for 
their practical knowledge, he would not pursue the subject 
further. 
Mr. Hartop said, with respect to the substitution of hot 
air for cold, of which his two friends seemed to approve, he 
wished to make one or two observations, because he was 
anxious that the question should be understood by the public 
at large. He was afraid that the introduction of hot air was 
erroneously termed an improvement in the iron trade, and, 
therefore, he was most anxious to concede any merit for the 
introduction of it. He was happy to say that few iron masters 
in Yorkshire had adopted what was termed this improvement, 
and hence when contracts were advertised for steam engines, 
but more particularly for steam packets and locomotive 
engines, they had the pride and gratification to see a clause 
introduced, that they should be made of Yorkshire iron. He 
believed there was only one work in Yorkshire which had 
adopted the hot air system. Now, there was one point which 
it was very important for the public to know. It had been 
stated that by the hot air blast double the quantity of iron 
might be made. He thought that perhaps on an average, 
one-half more might be made, but the quality of the article 
was deteriorated regularly in the market £1 per ton. He 
was contradicted in the British Association when he said he j 
could purchase it at 15s. less. That went the round of all | 
