NATIONAL POWER AND COAL 161 
stronghold against bacterial attack before it had made 
too devastating a progress. 
The coal which looks so black a lump in your hand, 
is not black if it is cut in thin enough sections ; but it 
is extremely difficult to cut such sections, because, as 
the slice is being rubbed down to be made thin, it tends 
to crack and split up. Without doubt many of the older, 
and still prevalent, mistaken notions about coal are 
due to the difficulties of section cutting. This art has 
been greatly improved in the last few years by Lomax, 
in this country, and Jeffrey and Thiessen in America, © 
so that the way is prepared for more satisfactory re- 
searches into coal structure. 
When a thin section is obtained it appears under the 
microscope as a mottled mass, grading from. opaque 
to transparent regions of deep coppery red to yellow. 
The untrained eye finds it difficult to see any structure 
in coal, save the most conspicuous and well preserved ; 
and the most conspicuous things in most coal sections 
are the spores, particularly the macrospores. These 
originally spherical or egg-shaped bodies are generally 
flattened, but often they appear to be not otherwise 
affected, and their thick, uniform walls show up as 
brilliant yellow or orange bands in the more opaque or 
granular masses of the coal. The conspicuous appear- 
ance of these spores, even in sections not otherwise 
very good for microscopic examination, early attracted 
attention to them, and probably partly accounts for the 
extreme view of their importance in coal formation taken 
by Huxley in his famous essay in the Contemporary 
Review for 1870. Dawson, who knew infinitely more 
about coal than did Huxley, answered him in the 
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