Coal tar

   Much of the coal we mine is used in making coke. When coke is made from coal, a sticky black liquid called coal tar is left over. Coal tar used to be thrown away. But now so many uses have been found for it that it is as valuable as the coal itself. It makes a good fuel. Besides, hundreds of products are manufactured from it. Who would guess that such things as perfumes and dyes and flavorings could come from something that was once just a nuisance? The first step in getting the products from coal tar is to heat the tar in big closed tanks. Pipes lead off from the tanks. Coal tar is a mixture of many chemicals. As it is heated, first one chemical and then another is driven off through the pipes. The many products of coal tar are made from these chemicals.