Poison matches. There are two kinds of phosphorus used in making matches, white and red. White phosphorus has an advantage and a disadvantage. White phosphorus is cheaper and, at one time, its use was quite common. White phosphorus is poisonous, however, and for this reason its use in making matches is prohibited by law in nearly all civilized countries. Men working in match factories which used white phosphorus were subject to a disease which caused the jaw bones to decay. The danger of small children being
poisoned by these matches is also evident.
Fortunately, chemists have discovered a method of making a form of phosphorus which is not poisonous. When white phosphorus is gently heated for several hours in a closed vessel from which air is excluded, it slowly changes in color and the no-poisonous red phosphorus is formed. In addition to the fact that it is not poisonous, red phosphorus has other advantages. Its kindling temperature is much higher than that of the white variety, and this makes red phosphorus less dangerous to ship and to store. Another method of making phosphorus safe for use in matches is to combine it with sulphur. To do this, the two elements are mixed and heated in the absence of air. The phosphorus sulphide, which is formed, is not poisonous.
1. With the help of his brother, Prometheus succeeded in presenting fire to man.
2. Fire gave man an advantage over other animals.
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