SECTION XVII 
MEASUREMENTS, MAP MAKING AND 
KNOTS 
1. measurements 
Every country has national standards of measures and 
weights which are made and kept by the governments 
as patterns, for measuring and comparing the instruments 
made for business purposes. The units of measure have 
been fixed by law, for it is most important that people 
and countries in dealing with each other shall know ex- 
actly what is meant by such words as yard, foot, pint 
and pound. 
The unit of length used in this country is the yard. It 
is divided into three feet and each foot into twelve inches. 
The foot refers to the length of a man's foot. It is said 
that the length of the yard was based upon the length of 
the arm of an English king, but that sounds like a fairy 
tale. Many of our units of distance and weight have 
been borrowed from the English and are more complicat- 
ed than those used by the French, whose unit of length 
is the meter. In 1799, or thereabouts, an international 
convention met at Paris to decide what the exact length 
of a meter should be, for several countries at that time 
were using what was known as the Metric System of 
Weights and Measures. It was finally agreed that the 
length of a meter should be equal to one ten-millionth 
of the distance on the earth's surface, from the pole to 
the equator, or 39.37 inches. 
At the same convention a unit of weight was determined. 
Because water is so important and familiar it was chosen 
as the basis for this unit. A cube of water at 40 centi- 
grade, and measuring on each edge 1/100 of a meter, was 
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