Microstructure of Coal from an Industrial Standpoint. 157 
It is an easy matter to distinguish between the soft humic coals 
and the hard cannel coals. The soft humic coal has a bright 
banded appearance, and it is divided by numerous cracks, mainly at 
right angles, which cause the coal to break into cubes. The hard 
cannel coal has a uniformly dull appearance, has few cracks, and 
is rather difficult to break. However, without the help of the 
microscope it is almost impossible to distinguish by their appear- 
ance the coals containing spores in a humic ground mass and those 
containing spores in a cannellized ground mass, particularly when 
the coals are in small pieces. Yet these are the coals which are of 
such vital importance to industry, particularly the iron and steel 
industry, for amongst them occur the true coking coals, the coals 
which are practically non-coking, and some excellent steam coals. 
The true coking coals are necessary for blast furnace coke manu- 
facture, while the practically non-coking are essential for producer 
gas manufacture. Steam coals are, as yet, necessary to most 
industries. The necessity for using the best available means of 
identifying the various classes of coal will be apparent, and in 
view of the fact that our coal reserves are not unlimited, it is 
wasteful to use a coal for one class of work when it is more suit- 
able for another. 
In a short paper before the Iron and Steel Institute I dealt 
with the various uses to which these coals should be put. (Booth : 
“ Economic Selection of Coal,” Journal of the Iron and Steel 
Institute, No. 2, Yol. CII.) 
The value of microscopical work in connexion with coal selec- 
tion was demonstrated very clearly during the late war at the works 
of Messrs. Armstrong, Whitworth, Openshaw, the firm with whom 
I am associated. No doubt all of you will be aware that restric- 
tions were placed upon long-distance transport of coal, and 
supplies could only be secured within a certain area. Neither 
could the usual sources within that area meet the increased 
demand, besides which usual supplies were sometimes curtailed 
owing to the Government having prior claims As a consequence 
new sources of supply had to be tapped. Of these coals there was 
no previous experience, and careful selection was necessary, yet 
very many of them were rejected on microscopical evidence alone, 
little or no chemical analysis being done, and no large scale tests 
run. This was a great saving of time to the laboratory staff. 
Though there were many anxious times due to traffic delays, etc., 
at no time was there any inconvenience caused by the fuel depart- 
ment being unable to supply suitable types of coal to meet the 
various requirements of the works.. If deliveries of a certain class 
of coal were temporarily stopped, it was possible, because of the 
more detailed knowledge gained from the microscopic work, to 
supply a similar class of coal or else the nearest type available. 
This knowledge made it possible to put into immediate effect any 
