"A mineral, papa, is a semi-metal, as they are called by the chemists, such as antimony, zinc, bismuth, and others. They are not inflammable, but are hard and brittle, and may be reduced into powder. Mercury or quicksilver has been classed with semi-metals. Shall I tell you how many metals there are, papa?" "If you please Theodore." "There are six, papa. Gold, silver, copper, tin, lead, and iron. The most precious metals, such as gold and silver, do not form the most splendid ones. The pyrites, which are a mixture of iron and sulphur, are more beautiful to the eye." "Very well remembered, Theodore. But you forget to class the magnet as a mineral." "I do not perfectly understand the nature of the magnet, papa." "It is a species of Iron found in iron mines," said Mr. Durnford, "which has the singular property of attracting metal. The ancients knew no means of finding their way at sea, but by the stars; of course when those celestial bodies were not visible, the sailor was frequently at a loss how to steer. A piece of steel is now procured, made something like a needle, but flat, about four inches long; this is rubbed with the loadstone, and then balanced exactly on two points or pivots, so that it may turn round freely. This needle when fixed in a box, is called the mariner's compass, and as it invariably turns toward the North, the sailors can now steer to any part of the world, which they could not do without the help of this piece of iron. The first knowledge of this useful application of the magnet is supposed to come from Marco Polo, a Venetian, in the thirteenth century; but it is said to have been known to the Chinese." "We will now take a view of those PRINTS," [Illustration: _Print-seller_] said Mrs. Durnford, "I am as fond of the sight as any of my children." "A fine engraving is very valuable," replied Mr. Durnford, "and I have lately seen some on wood, which pleased me extremely. Albert Durer, was I believe the first inventor of engraving on wood. Etching on copper was not known until Henry the Sixth's time." "What is that picture, papa, which that lady has just turned aside?" enquired Miss Durnford. "It is the representation of one of the most important events in English history, my love. Namely, the signing of a deed called Magna Charta, by the weak-minded and worthless King John. The place is called Runnymead, near Windsor; where the barons compelled John to sign that famous deed, which laid the foundation of that freedom, which for centuries has been the glory, boast, and security, of the English people. I will buy the print, that I may have the pleasure of placing underneath it, those fine lines by Dr. Akenside, which were intended for a pillar or monument of that transaction at Runnymead."