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XII. Further Observations on the Process for converting cast 
into malleable Iron. In a Letter from Thomas Beddoes, M. D. 
to Sir Joseph Banks, Bart. P. R. S. 
Read May 3, 1792. 
DEAR SIR, 
Since I described to you the process known among the 
workmen by the term, puddling of iron, I have several times 
reconsidered the explanation I attempted, in the same letter, of 
the phenomena it presents. My explanation could not indeed 
but be in great measure conjectural ; and subsequent reflection 
excited in my mind a very lively wish to ascertain, in a decisive 
manner, the nature of the process. The following experiments 
will, I flatter myself, serve to determine the degree of confi- 
dence with which the principal points of my theory may be 
received, though they will not afford a solution of all the ques- 
tions which my former communication might suggest to an 
acute philosopher. 
They were undertaken in order to ascertain, 1. whether any 
elastic fluids are really extricated during the conversion of cast 
into malleable iron ; and 2. what is their nature ; and 3. whe- 
ther they vary at different periods of the process, as I con- 
cluded from the appearances in the furnace. It seemed of less 
consequence to ascertain their quantity. I did not, however, 
neglect this object of inquiry, but you will find that some very 
curious circumstances prevented me from attaining it. 
