THE LIFE OF A PRIMROSE, 159 
oxygen gas, and they tell you that they have been 
set free by the green cells which have torn from them 
the carbon of the carbonic acid in the water. 
But what becomes of the carbon ? And what use 
is made of the water which we have kept waiting all 
this time in the leaves ? Water, you already know 
is made of hydrogen and oxygen ; but perhaps you 
will be surprised when I tell you that starch, sugar, 
and oil, which we get from plants, are nothing more 
than hydrogen and oxygen in different quantities 
joined to carbon. 
It is very difficult at first to picture such a black 
thing as carbon making part of delicate leaves and 
beautiful flowers, and still more of pure white sugar. 
But we can make an experiment by which we can 
draw the hydrogen and oxygen out of common loaf 
sugar, and then you will see the carbon stand out in 
all its blackness. I have here a plate with a heap of 
white sugar in it. I pour upon it first some hot 
water to melt and warm 
it, and then some strong 
sulphuric acid. This acid 
does nothing more than 
simply draw the hydrogen 
and oxygen out. See! in Carbon r^^fr^ white sugar. 
a few moments a black 
mass of carbon begins to rise, all of which has come 
out of the white sugar you saw just now.* You see, 
* The common dilute sulphuric acid of commerce is not strong enough 
for this experiment, and any child who wants to get pure sulphuric 
acid must take some elder person with him, otherwise the chemist will 
not sell it to him. Great care must be taken in using it, as it burns 
everything it touches. 
