348 ILLINOIS STATE ACADEMY OF SCIENCE 



The chart is interesting because it illustrates at least 

 the chemical method ordinarily employed for determin- 

 ing whether a given coal would coke or not. For ex- 

 ample, if the ratio of hydrogen to oxygen is 1 :1 or even 

 34:! or 75 per cent of the oxygen percentage, then the 

 coal is considered to be in the coking class. But if the 

 ratio of hydrogen to oxygen is, let us say, 0.6:1, that is 

 60 per cent or less, then the coal is classed as non-coking. 

 When one insists on a definition of these terms from 

 those who make use of them, their answer really amounts 

 to this: ''A non-coking coal is one which is not being 

 coked." They do not say it is one that cannot be coked, 

 hence, fortunately the door is left open for the foolish 

 to venture in. 



For a better emphasis upon this oxygen factor, to be 

 discussed presently, let us make a new^ set of ratios from 

 these charted values, — a ratio of the inert or oxygen 

 compounds to the volatile combustible residue, not be- 

 cause we wish to introduce a new ratio as a coking index, 

 but simply as emphasizing from another angle the oxy- 

 gen content of these coals. Such ratios would then ap- 

 pear as follows : 



(1) 4:14, or approximately 30% 



(2) 14:21, or approximately 60% 



(3) 21:20, or approximately 100% 



From the standpoint of the usual classification, those 

 coals which j^ass beyond a ratio between the oxygen 

 compounds and the hydrocarbons or volatile combustible 

 of 1 :2 or 50%, bring us into the class of non-coking coals. 



It will be evident at once that we have here no expla- 

 nation whatever as to the reason for coking or non- 

 coking properties. The use or status to be given to 

 analytical results of this sort is that of a definition only. 

 It is a definition moreover which is not even empirical 

 in its derivation. The most that can be said of it is that 

 its basis is that of a coincidence — and any case which 

 might arise to break the coincidence would vitiate the 

 value of the definition. 



