"He had some thick flannel bags, one inside the other, and he poured into them some dirty, muddy water. In a short time we saw the water trickle through the flannel, into a basin he held under it. But the water that came through was clear, and not muddy.
"Why did the water drip through flannel, Norah?" "I suppose," said Norah, "it is because the flannelis porous."
"Quite right. But why didn"t mud come through too? I think I ought to tell you that," he added. "Itis because the holes are too small to let bits of mud through. The water could pass through, but not the mud.
"Now let us think about the sugar. The coarse sugar is mixed with some lime, and put into water to dissolve. The syrup is then poured into bags made of thick folds of woollen cloth, and left to drip through into a vessel below. You will see now, I think, why the syrup which drips from the bags is quite clear.""The pores in the bags, I suppose," said Norah, "won"t let the dirt pass.""Yes," said Fred, "that"s right. But, although the syrup is clear, it is still brown. It is next made to run through a bed of small charcoal, made of burnt bones. All its brown colour goes as it passes through the charcoal.
