Whatever way you do it, whether by heat or cold, if it is not disturbed, but allowed to go into its regular forms, it is called crystallisation."

"You have laboured through your explanation, Lucy, tolerably well," said her mother.

"But there is one other thing more you should say, Lucy," said Harry.

Say it for me," said Lucy.

་

"That different substances form into crystals of different shapes. Crystals of substances of different sorts, as I have just been learning," continued Harry, "have always a certain regular number of sides; so that when you see the crystal, after counting the sides, you can tell of what it is composed; or you can tell beforehand the number of sides and the shape of the crystals that will be formed from any known salt or substance, which you have dissolved, and left to crystallise."

"For instance, alum," cried Lucy. "The alum which was dissolved in the hot water, and which Miss Watson has left there to

crystallise, we know, will be in the same shaped crystals as these in this first basket. I will count, and tell you the number of sides."

Harry said, he thought that Miss Watson could, if she pleased, tell the number of sides without counting them, and so she did.

"How difficult it must be," said Lucy, "to get by heart, and to keep in the memory the number of sides which belong to all the different kinds of crystals!"

"You need not do that," said Miss Watson. "Lists of them are to be found in many books, to which you can refer when you want them."

"But you knew alum without looking at any book," said Lucy.

"Yes, because I had been accustomed to see its crystals," said Miss Watson. "As I told you before, many of the facts in chemistry or mineralogy, which it would be difficult to remember separately, or merely from having read or heard an ac

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count of them, are easily fixed in the mind, by trying experiments, and by connecting those facts with others.

Miss Watson told Lucy that she had become particularly fond of this study, because her father was a chemist, and she had often been in his laboratory while he was at work. "Unless I had seen the actual things I should not have remembered the descriptions of them, I am sure,” said she; "and besides, I was so much interested in my father's experiments, and so curious to know whether they would turn out as he had previously expected, that the whole was fixed in my memory. Unless I had had somebody with whose pursuits I could sympathise, and in whose discoveries I felt an interest, I should soon have forgotten even the little I had learned."

"But does not it make you happy?" Lucy asked.

if

"Are you, or are you not happier than had not this pursuit?" said Harry.

you

Miss Watson smiled at the earnestness with which they questioned her; and answered, that she thought she was much happier for having this taste, and this occupation. She said it never prevented her from doing other things, which were more necessary. To this her brother added his testimony.

"Her being something of a chemist has not spoiled her hand for being a good confectioner," said he. "On the contrary, it has improved it, for she knows the reasons for what she is doing. All confectioners and cooks must be chemists for so much, but they do not know the reasons why they succeed one time, and fail another. With them it is all knack, and hap-hazard, or what we call practice, at best. Now," continued Mr. Watson, "here is an old receipt book, which belonged to the greatgrandmother of a noble family, famous in her day, no doubt, for her cakes, and puddings, and confectionaries, and cures for all manner of sprains, and aches, and

K 2

bruises: look at any of these, and you will see what nonsense half of them are. How many useless ingredients are put into the receipt, either on purpose to puzzle other people, or from ignorance, and a sort of superstitious belief, that there was a mystery in doing these things."

Harry and Lucy amused themselves by looking at some of these old receipts, which, however, were hard to decipher, the ink being yellow, and the spelling old and incorrect.

The next day was Sunday. Harry and Lucy went with their father and mother, and Mr. Watson and his family to church. The church was in the village near the house. As they were walking home, Mr. Watson asked if they would like to see some of the houses in the village, where his workmen lived, and the cottages in the neighbourhood. Harry and Lucy were glad to take this walk, and Harry kept close to Mr. Watson wherever he went.

In one cottage, the master of the house,