Supplementary Chapter 



319 



the author's figures for ultimate composition of the products 

 investigated : 



The method of investigation was chiefly directed to mea- 

 suring the phases of exo- and endothermic change as heat is 

 applied, measured as temperature. In the case of cellulose 

 the first exothermic change is sudden and takes place at a 

 definite temperature, 345. In the case of the pseudo-carbon 

 and lignite the exothermic changes are less extreme and are 

 spread over a wider range of temperature, 280^-420. 



In the anthracites this phase is not observed below 650- 

 840. The several types of coal are characterised quite 

 definitely in this respect, and the complementary endothermic 

 phases are equally definite. Thus the pseudo-carbon has a 

 pronounced endothermic phase at 3oo-4oo. The author's 

 methods and graphic records, when collated with the study of 

 the products of distillation in the successive phases, will furnish 

 a well- denned picture of these highly complex resolutions. 

 (See pp. 68-70 ; p. 154 ; and pp. 204 206.) 



In this perspective of the subject we must group together 

 the entire range of carbohydrates and their natural history as 

 plant products (see pp. 238-241). 



The simplest carbohydrates under the action of heat afford 

 indications of the condensations which are characteristic of 

 the decay of vegetable matter to form the ' natural ' products 

 of the series (Humus Peat Lignite Bituminous Coals 

 Anthracite). 



Some interesting developments of this theme will be found 



