Microstructure of Coal from an Industrial Standpoint. 159 
now a vast accumulation of knowledge on the behaviour of coals 
under very diverse conditions of treatment, but strictly speaking 
the results are only applicable to those coals upon which the 
results were obtained. It is usual for the various workers to give 
a chemical analysis of the coal upon which they have worked ; 
some give an ultimate analysis, others a proximate, though they 
often give it without any particulars as to the conditions of the 
analysis. As already pointed out these chemical analyses may be 
entirely misleading. If a description and illustration of the micro- 
structure of the coal had been included as a matter of course, the 
value of this accumulated knowledge would be enormously 
enhanced. In all probability it would be possible from a study of 
the matter published to draw conclusions in regard to the influence 
of the coal constituents on the properties. Further means of 
verification and study would have suggested themselves. As it is 
the greater part of the published works lack the essential common 
factor whereby the whole can be correlated. A great step forward 
will have been made when workers on coal include a micro- 
analysis in their results. Had such a course been followed in the 
past many misleading statements would never have been made. 
Various workers, for instance, have implied that the spore exines 
were resinous. It is now known that the “ resinous ” matter in coal 
is the cause of coking, and that after treatment with pyridine, in 
which the “ resinous ” matter is soluble, coals lose their coking pro- 
perties ; yet spore exines are found in the insoluble portion of the 
coal. Again, coals in which spore exines predominate are practic- 
ally non-coking. 
This microscopical study of coal constituents is essentially the 
work of the trained palseobotanist. Stopes and Wheeler in their 
previously mentioned monograph summarize the possibilities in 
this direction, and describe many of the chief constituents of the 
coal substance. But before much can be said about the coal 
constituents methods will have to be devised for separating the 
chief ones and studying their behaviour under various conditions. 
The chemist must work side by side with the palseobotanist and 
their results correlated. Real progress can only be made by 
combining the work of the two. 
The microstructure of coal can give most valuable infor- 
mation, not only to the fuel technologist and palseobotanist, but 
also to the geologist. The Geological Survey and the Fuel 
Research Board are co-operating in a survey of the British coal 
seams. It is to be hoped that a detailed account of the micro- 
structure of the whole thickness of the seams will be included in 
their report. Such a survey is long overdue. From a national 
point of view it will supply most essential information as to the 
available resources of the various classes of coal. The coal owners 
and users would undoubtedly benefit by such a survey. Since the 
