1/2 THE FAIRY-LAND OF SCIENCE. 
pick for yourself out of the coal-scuttle. Our work 
to-day is to relate the history of this black lump ; to 
learn what it is, what it has been, and what it will be. 
Fig. 45- 
Piece of coal. 
a, Smooth face, showing laminae or thin layers. 
It looks uninteresting enough at first sight, and yet 
if we examine it closely we shall find some questions 
to ask even about its appearance. Look at the 
smooth face of this specimen and see if you can 
explain those fine lines which run across so close 
together as to look like the edges of the leaves of a 
book. Try to break a piece of coal, and you will find 
that it will split much more easily along those lines 
than across the other way of the lump ; and if you wish 
to light a fire quickly you should always put this 
lined face downwards so that the heat can force its 
way up through these cracks and gradually split up 
the block. Then again if you break the coal carefully 
along one of these lines you will find a fine film of 
charcoal lying in the crack, and you will begin to sus- 
pect that this black coal must have been built up in 
