22 THE FAIRY-LAND OF SCIENCE. 
learn the difference between the animal which builds 
up the red coral as its skeleton, and the group of 
animals which build up the white ; and you will look 
with new interest on our piece of white coral, as you 
read that each of those little cups on its stem with 
delicate divisions like the spokes of a wheel has been 
the home of a separate polyp, and that from the sea- 
water each little jelly animal has drunk in carbonate 
of lime as you drink in sugar dissolved in water, and 
then has used it grain by grain to build that delicate 
cup and add to the coral tree. 
We cannot stop to examine all about coral now, we 
are only learning how to learn, but surely our speci- 
men is already beginning to grow interesting ; and 
when you have followed it out into the great Pacific 
Ocean, where the wild waves dash restlessly against 
the coral trees, and have seen these tiny drops of jelly 
conquering the sea and building huge walls of stone 
against the rough breakers, you will hardly rest till 
you know all their history. Look at that curious cir- 
cular island in the picture (Fig. 3), covered with palm 
trees ; it has a large smooth lake in the middle, and 
the bottom of this lake is covered with blue, red, and 
green jelly animals, spreading out their feelers in the 
water and looking like beautiful flowers, and all round 
the outside of the island similar animals are to be 
seen washed by the sea waves. Such islands as this 
have been built entirely by the coral animals, and the 
history of the way in which the reefs have sunk gra- 
dually down, as the tiny creatures added to them inch 
by inch, is as fascinating as the story of the building 
of any fairy palace in the days of old. Read all this, 
