Specific surfaces of the macropores and transition

The effect of mineral matter is so small that it is completely negligible compared to the combined specific surface of the macropores and transition pores in coals with scattering curves which have a shoulder. 

In Table 1 we list the sum of the specific surfaces of the macropores and transition pores and also the specific surfaces obtained by low temperature nitrogen adsorption and by adsorption of carbon dioxide at room temperatures. The nitrogen and carbon dioxide specific surfaces are taken from the PSOC data bank, except for coal PSOC 105. Since the specific surfaces in the data bank for this coal appeared questionable, they were remeasured by R. G. Jenkins at Pennsylvania State University. 

At the time we wrote the manuscript for Reference (7), we were unable to relate the high fraction of transitional pores found in many of the coals to any other property of the coals. We have now concluded (11) that there are inflections in the scattering curves only for coals with fixed carbon contents in the interval from about 72% through 83% per cent (dry, mineral-matter free) and that for these coals, the specific surface of the transitional pores is appreciably larger than the specific surface of the macropores. As would be expected from our interpretation of the inflection (11), the specific surfaces of the transitional pores in all of the subbltumlnous coals in Table 1 except PSOC 138 are much larger than the specific surfaces of the macropores, and there is a tendency for the total x-ray specific surfaces [i. e., the sum of the specific surfaces of the macropores and transitional pores, as calculated by... 

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