英文科学读本 第一册·Lesson 28 Loaf Sugar

Lesson 28 Loaf Sugar

Oh, do come and tell me how they make that coarse, brown, soft sugar into the hard, white loaf sugar. said Norah.

The children had just settled down for their evening chat, and our little girl had been thinking about that white sugar all teatime.

Well, said Fred, "before I tell you that, I will explain something, that teacher showed us today."

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 flannel is porous."

Quite right. But why didn't mud come through too? I think I ought to tell you that, he added. "It is 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."

The clear syrup is then put into large copper pans and boiled.

Yes, and the rest is easy to see, said Norah. "The water boils away, and the syrup gets thicker and thicker."

When it is thick enough, it is poured into large molds to cool, said Fred. "It comes out of the mold as a hard, white, solid sugar-loaf."

Norah would like to know, added Will, "that the part which drains away from the mold is our golden syrup."

SUMMARY

The hard, white, loaf sugar, which we use for our tea, is made from coarse, brown, moist sugar. This coarse sugar is first mixed with lime, and then put into water to dissolve. It forms a syrup, which is made to trickle through porous bags, and then through charcoal. This takes away its brown color and leaves it clear, after which it is boiled. As the water boils away, the syrup thickens, and it is put into molds to cool. Some of it will not become solid; it drains away and forms Golden syrup.