﻿PROXIMATE ANALYSIS OF COALS. 43 



loss in the case of certain non-coking coals; that no evidence has been given as 

 to the amount of such loss, while in the light of certain experimental determina- 

 tions which are described, they state that the loss can only have been insignificant. 

 It has been observed in this laboratory that the error from this source on our 

 coals is very large, possibly amounting to a few per cent in some cases. It has 

 also been found that this error could be largely if not entirely eliminated 

 by expelling the moisture and most of the volatile matter at a low heat 

 before subjecting to the full flame of the Bunsen burner for seven minutes. Four 

 to five minutes gentle heating are sufficient to do this. With this exception the 

 official method has been followed in detail." 



Since the above article went to press, a paper entitled "Some Experi- 

 ments on the Determination of A T olatile Combustible Matter in Coals and 

 Lignites" has reached us, in which the modification used by the fuel- 

 testing plant of the United States Geological Survey in the analysis of 

 lignitic and sub-bituminous coals is described. It is almost identical with 

 the one we have used in the analj-sis of the coals occurring in these Islands 

 when the official method is inapplicable. The modification which we have 

 heretofore employed is substantially as follows : 



The sample of coal to be analyzed is placed in a platinum crucible of twenty 

 or thirty cubic centimeters capacity and subjected to a low heat, just enough 

 to expel the volatile combustible matter at such a rate that it will burn in 

 a very small flame at the edges of the crucible lid. The heat is regulated by hold- 

 ing the burner in the hand and directing it upon the bottom of the crucible. The 

 flame is slowly moved back and forth under the crucible, the heat is gradually 

 increased as the escaping gases burn lower and lower and finally the crucible 

 is heated for seven minutes over the regulation Bunsen flame. 7 



This method is obviously an improvement in certain cases and was 

 used as a provisional or tentative one until time conld be found to 

 investigate the subject thoroughly. 



My data do not agree with the statement of the Committee on Coal 

 Analysis that the error due to rapid heating is insignificant. They show 

 that there is a very large mechanical loss when the official method is ap- 

 plied to certain Philippine Coals, confirming the results of experiments on 

 American non-coking coals. It is not even necessary to have analytical 

 data to prove that there are mechanical losses from some non-coking 

 coals when the volatile matter is rapidly expelled, as it is by the official 

 method, for it is amply indicated by the shower of incandescent carbon 

 particles which are driven off during the first one or two minutes heating. 

 It is hoped that this paper will demonstrate how these losses can be 

 avoided. 



Somermeier, 8 in referring to the modified process of the fuel-testing 

 plant, says: ''The difference in results obtained by three, four and five 



'Somermeier, E. E. : J. Am. Chem. Soc. (1906), 28, 1002. 



7 By the regulation Bunsen flame I understand one which, when nonluminoua 

 and unobstructed, burns 20 centimeters high. 



8 Loc. cit. 



