"I would conduct steam through pipes under the pan that holds the sugar."

"You are both of you on the right road to the principal improvement in sugar boiling," said their father; "but yet you have not fully mastered the difficulty. By the method that you have suggested, one might be able to heat the sugar, but certainly not to boil it; for you know that a solution of sugar, if in an open vessel, requires a stronger heat to make it boil than water does."

"But I should think," said Harry, "that by confining steam, it could be made much hotter than boiling water; and in that case, with compressed steam, I might be able to boil syrup."

"You might so," said his father; "and some persons do boil sugar in that way; but high-pressure steam (as it is called) is hazardous to deal with; and by this method also we risk the overheating of the sugar. Turn your thoughts, therefore, another way, and instead of raising the

temperature of the steam, consider whether there are not means of making syrup, or any other fluid, boil at a lower temperature than when exposed to the common atmosphere."

Harry considered for some time, and at length said, "I am not certain whether I could succeed with syrup; but I have seen water made to boil, when only moderately warm, by putting it under the receiver of an air pump."

"How did that happen?" said his father.

"Because there was a vacuum," said Harry, "there was no pressure of the atmosphere. If we could place the sugar pan under the receiver of an air pump, that, perhaps, might do; but the quantity of sugar to be boiled puzzles me, father; the sugar vessels are very large, I believe. I could only boil a very small quantity in an air pump; so that, after all, it would not do I suppose."

"Why will not it do?" said his father.

"Do not give up your ideas too hastily; till you are sure that they will not answer, never fly off to any thing else. Do not fix your imagination upon the particular receiver of the air pump you have seen. To be sure you could not conjure a sugar boiler into that small receiver."

"No, to be sure," said Harry, laughing: then becoming quite grave again, he went on thinking. "How shall I manage it? It is impossible to blow a glass large enough for the receiver."

Why do you stick to the notion of a glass receiver, Harry?" said his father. "Do think it essential to the having

you

a vacuum, that it should be produced in glass?"

"it is not

"Certainly not," said Harry, necessary by any means. I only thought of the glass one, because that was the only receiver I had seen; but I perceive that any other substance that is air-tight will do as well as glass. How foolish I am! I remember now the pump, and the steam

engine, where the vacuum is large enough; or a vessel might be made as large as could be required for the purpose."

"Now you have it, Harry. The sugar is boiled in a vacuum, and that vacuum is produced by means of an air pump. The exact details I do not know, having never seen it done myself, but I hope we shall see it to-day, and so now let us set out."

THE sugar house, which Harry and Lucy went to see, was a large building of eight stories high. The first circumstance which struck them on entering it was, that in several spacious rooms through which they passed, and in which the work seemed to be going on, there were not many workLucy supposed that it was the hour of dinner, as had happened in some other manufactories which they had seen: but she was told that this was not the case; and that all the men, who were ever employed in this sugar house, were now there. Few only were necessary, because

men.

so much was done by machinery. In truth, the men seemed of little importance. It appeared as if they were employed only as under-servants to the machines, and to do trifling things, which the mechanic and the chemist had not thought it worth their while to invent the means of effecting in any other other way.

The large rooms and passages, through which they passed, were all warm, as Lucy observed, and yet she could not anywhere perceive any fire. She asked how they were warmed, and was told that she would soon see, as they were going to the place from whence the warmth came. Their guide, the gentleman who was so kind as to show them these works, took them to a building, separate from the rest, in which there was a steam engine. The fire under its boilers was the only fire used in these works. All the rooms were heated by steam that passed through pipes in the walls, or under the floors.

Harry was here perfectly satisfied, and he looked delighted and proud, when he