Alan Craig, age 7, of Peoria, Illinois, for his question:

Why do they measure a horse in hands?     

People have been admiring horses for many thousands of years. Our distant ancestors tamed them long before they l6arned to write. At that time, they had not learned much about arithmetic, either. Their ways of measuring things were very simple. Afoot was the length of a man's foot. Yards were paced off in strides.

Finger joints and elbow joints were used as rulers. A span was the distance between the fingertips of an outspread hand: But when hands were used to measure the tallness of a horse, the measure was taken from a hand spread flat with the fingers close together. On a modern ruler, this horse measuring hand equals four inches.     Horses are still as popular as they were 10,000 years ago. And all this time their human admirers have not changed their old way of measuring them. The height of a horse is taken from the ground to his withers, the point at the back of his shoulders. Naturally, we no longer do the job with human hands. But if a horse measures 56 inches from the ground to his withers, it is polite to say that he stands 14 hands high.