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 complicated 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 centigrade, and measuring on each edge 1/100 of a meter was taken and called a gram, which is about equal to 15 of our grains. All peoples find it necessary in the house, out in the open and in nearly all forms of occupation to measure and weigh in order to accomplish their work. It is part of a Scout's preparedness to know how to measure and weigh and how to judge measurements and numbers without using measures and weights. There are rules for determining length and weight, and it is important to understand them. Measuring a distance means to find out the length of the straight line from one point to another. To get a straight line in the open when walking fix the eyes upon two objects directly in front, one nearer and smaller than the other. With eyes high walk toward these objects keeping them always in line. When approaching the first one choose another to take its place in line with it and the second. Always have two objects in direct line with the eyes. This method can be used in marching, rowing, swimming, and when staking out the points of triangles for measuring distance and height, as it will give the shortest distance between two points. There are three general methods of measuring distance accurately. (1) chaining or taping; (2) telemetry, and (3) triangulation. Less accurate means of measuring are by sound, pacing and timing. (1) Chaining and Taping. The regulation chain or tape used by surveyors is 100 feet long. A Scout may use a shorter line but must follow the same rules. Three things must be kept in mind when using a line. a. The straight distance between two points is to be obtained. b. The point where the end of the line comes each time must be marked. c. The line must be stretched tight. This method can be used in measuring off the distance for pacing to obtain the average length of one's pace, as suggested in a later paragraph under Useful Personal Measurements.