Harson, "although, as in this poor woman's case and in many others, gold is not the best thing to find. It often brings with it so much sorrow and sin as to be a curse to its owner. The only safe treasure is that laid up in heaven, where 'neither moth nor rust doth corrupt, and where thieves do not break through nor steal,'

"From the very earliest times the oak has been used for shipbuilding. The Saxons, we are told, kept a formidable fleet of vessels with curved bottoms and the prow and poop adorned with representations of the head and tail of some grotesque and fabulous creature. King Alfred had many vessels that carried sixty oars and were entirely of oak. A vessel supposed to be of his time has been discovered in the bed of a river in Kent, and after the lapse of so many centuries it is as sound as ever and as hard as iron."

"Do oak trees ever have apples on 'em?" asked Clara. "In a story that I read there was something about 'oak-apples.'"

THE OAK-GALL INSECT
(Cynips).

"They are not apples such as we eat, or fruit in any sense," said her governess. "They are the work of a species of fly called Cynips, which is very apt to attack the oak. 'The female insect is armed with a sharp weapon called an ovipositor, which she plunges into a leaf and makes a wound. Here she lays her eggs; and when she has done so, she flies away and we hear no more of her. But the wound she has made disturbs the circulation of the sap. It flows round and round the eggs as though it had met with some foreign body it would fain remove. Very soon the eggs are in the midst of a ball-like and fleshy chamber--the most suitable provision for them, and one which the parent-insect had provided by means of puncturing the leaf. As the eggs are hatched the grubs will find themselves safely housed and in the midst of an abundance of food.'"

OAK-APPLES.

"Well," exclaimed Malcolm, in great disgust, "apple is a queer name for a ball full of little flies!"

"It's a very pretty ball, though," said Miss Harson, "with a smooth skin and tinged with red or yellow, like a ripe apple. If it is cut open, a number of granules are seen, each containing a grub embedded in a fruit-like substance. The grub undergoes its transformation, and in due course emerges a perfect insect. These pretty pink-and-white apples used to be gathered by English boys on the twenty-ninth of May, which was called 'Oak-Apple Day.'"

"Did they eat 'em?" asked Edith.

"I do not see how they could, dear," was the reply; "they were probably gathered just to look at. Yet 'May-apples,' which grow, you will remember, on the wild azalea and the swamp honeysuckle, are often eaten, and they are formed in the same way; so we will not be too positive about the oak-apples."

"What are oak-galls, Miss Harson?" asked Malcolm. "Are they the same as oak-apples?"

"Not quite the same," was the reply, although both are produced by the same insect. This is what one of our English books says of them: 'When the acorn itself is wounded, it becomes a kind of monstrosity, and remains on the stalk like an irregularly-shaped ball. It is called a "nut-gall," and is found principally on a small oak, a native of the southern and central parts of Europe. All these oak-apples and nut-galls are of importance, but the latter more especially, and they form an important article of commerce. A substance called "gallic acid" resides in the oak; and when the puncture is made by the cynips, it flows in great abundance to the wound. Gallic acid is one of the ingredients used in dyeing stuffs and cloths, and therefore the supply yielded by the nut-gall is highly welcome. The nut-galls are carefully collected from the small oak on which they are found, the Pyreneean oak. It is easily known by the dense covering of down on the young leaves, that appear some weeks later than the leaves of the common oak. The galls are pounded and boiled, and into the infusion thus made the stuffs about to be dyed are dipped,'"

"I should think," said Clara, "that people would plant oak trees everywhere, when they are so useful. Is anything done with the bark?"

"Yes," said her governess; "the bark, which is very rough, is valuable for tanning leather and for medicine. The element which has the effect of turning raw hide or skin into leather is called tannin; it is also found in the bark of some other trees and in tropical plants."

"Didn't people use to worship oak trees," asked Malcolm--"people who lived ever so long ago?"

"You are thinking of the Druids, who lived in old times in Britain and Gaul," replied Miss Harson, "and whose strange heathen rites were practiced in oak-groves; and they really did consider the tree sacred. These Druids have left their traces in some parts of England and France in rows of huge stones set upright; and wherever an immense stone was found lying on two others, in the shape of a table, there had been a Druid altar, where the priest offered sacrifices, often of human beings. So horrible may be a so-called religion that men themselves devise, and that has not come from the true God.

DRUIDIC SACRIFICE.