Lewis.] ll-G [Dec. 2, 



concludes that Dopplerite consists of one or more of the humous acids, and 

 shows that the portion of peat soluble in alkali is identical with Doppler- 

 ite, and tliat compact peat contains minute black particles of Dopplerite. 

 Peat is therefore a mixture of Dopplerite with partially decomposed plant 

 remains ; wliile Dopplerite itself may be regarded as a homogeneous peat 

 in which all organisms have been decomposed. He shows that in difierent 

 peats the proportion of Dopplerite, or part soluble in alkali, increases with 

 the age of the peat, while the contrary is the case with mineral coal. Thus 

 while in a recent peat but 25-30 per cent, was soluble, in an old compact 

 peat, the proportion was 77 per cent. On the other hand, the solubility of 

 coal, decreases with its age, as shown in the following table, where the 

 figures represent the degree of solubility in alkali : 



(Dopplerite) (100) 



" Slate coal," a woody lignite, Diluvial 75 



Brown coal 42 



" Pitch coal, " Upper Miocene 10 



' ' Lower " 5 



Bituminous coal, Eocene 2.3 



" " Carboniferous trace. 



Anthracite 



He concludes that in the formation of coal from peat, the first step of 

 the process is the formation of Dopplerite, and the second the gradual 

 transformation of the latter into a material less soluble in alkali, and richer 

 in carbon. 



Several other European localities for Dopplerite have more recentlj' 

 "been discovered. 



A substance resembling Dopplerite in the peat of Hiignetswyll, St. 

 Gall, Switzerland, mentioned by Deicke,* burns with flame, and is re- 

 garded by Kenngott as having characters more iieavly approaching those 

 of Pyropissite or Melanchyme. It possibly is more analogous to the sub- 

 stance from Scrantou. 



Dopplerite has not as yet been discovered in America, While the sub- 

 stance described in the present paper more nearly resembles Dopplerite 

 than any other known mineral, it differs, as already shown, both in com- 

 position and in its behavior when burning. 



A distinguishing feature of the Scranton mineral is its very low per- 

 centage of carbon. Dopplerite has almost the precise composition of peat, 

 and peat, as is well known, contains more carbon than is contained in 

 wood. Yet the Scrantou mineral contains even less carbon than is con- 

 tained in wood.f The empirical formula of the Scranton mineral gives 



*Neues Jahr. f. Nim., 1858, p. 663. 

 fThe composition of peat is about: 



C H O -1- N Ash. 



61 6 33 =100 



The average composition of wood is: 



C H O + N A.sh. 



49.6 6.1 13.1 1.2 -=100 



V. Coal, its Historj' and Uses. Thorpe, etc., p. 165. 



