LEAVES 113 



itself out ; the black jiortion that remains will be a 

 piece of charcoal not \er\' much smaller than the 

 ori<;inal match. 



Of course, in the [process of burnin;^, the match 

 has lost the resin, and other or^^anic substances 

 which were stored up in the cells of the wood ; all 

 these ha\e passed into the air, and onl\- the carbon 

 remains. If, houexer, instead of tiiis slow manner 

 of combustion, we had set light to a whole box 

 of matches so that it burnt fiercely, the flame 

 would have been strong enough to consume the 

 charcoal, and nothing would then be left but 

 mineral ashes. 



When charcoal burners are at work in a forest, 

 we may see them making a stack of wood, which 

 they cover with a thick la)'er of clay so that the 

 wood may burn away ver\- slowly ; in this case 

 the charcoal w ill be left in the same way as when 

 we burnt the single match. 



As long as the upper side of leaves are .soaking 

 in the sunlight, starch is being formed, as I have 

 described ; but during the night the starch thus 

 formed is dissolved, and passing through the leaf 

 fibres finds its wa}- into every part of the plant, 



