The milk turns sour because a little microbe, known as the milk microbe gets into it, and being very fond of the sugar which is in the milk, turns this sugar into an acid. If we could keep milk entirely away from the air after the cow is milked, it would not turn sour, but as soon as it is exposed to the air these microbes which are constantly in the air, drop into the milk. They are alive, although invisible to the naked eye. If when they drop into the milk it is warm enough for them to get in their work so to speak, they fall upon the sugar in the milk and turn it into the acid. Their attempt to sour the milk can be overcome by keeping the milk at a low temperature in the refrigerator, but as soon as the milk is taken out of the refrigerator and left out long enough to become warm, the microbe begins to work and the milk cannot be made sweet again. If the milk is boiled as soon or shortly after the cow is milked, the sugar in the milk is changed in such a way that the microbe cannot feed upon it. [Illustration: A PERSIAN RUG WEAVER AT WORK.[3]] [3] Pictures and descriptions by courtesy of Hartford Carpet Co. The Story in a Rug What Are Carpets and Rugs Made Of? The choicest wool of the world is used in the manufacture of carpet. In order to give satisfactory service carpet must be made of wool that is of a tough quality and has a long fiber. Such wool is not produced in America, and the markets of the distant lands that supply it are practically exhausted to supply the American manufacturers. Most of the wool used comes from Northern Russia, Siberia and China. It is shipped in bales. When it arrives at the mill there is much to be done before the wool is ready for any process of manufacturing. How Long Have People Used Carpets? The art of weaving stands foremost among the ancient industries. It came into being in the sunrise lands of the East where color has endless charm and variety and where figure is made to serve the purpose of fact and fancy. The art of weaving rugs is older than Egyptian civilization. Stone carvings made when Egypt was yet unborn were reproduced in rugs. At what period the loom was first used is impossible to tell. An ancient Jewish legend claims that Naamah, daughter of Tubal-Cain, was the inventor of the process of weaving threads into cloth. There are other indications that the ancient Hebrews were the first weavers. Mythology also tells of beautiful maidens weaving exquisite patterns for the gods. Most of us are familiar with the story of Jason who set sail on the Argo in search of the Golden Fleece, arrived at the kingdom of Aeetes, won the hand of Medea, the daughter of Aeetes, who eloped with him after he had secured the coveted fleece.