The league is equal to three miles, the land league being equal to three United States statute miles (15,840 feet) and the United States ma rine league to three nautical miles (18,240.6 feet). Its value varies in different countries. The marine league is the distance from shore over which a country has jurisdiction under in ternational law.
The degree is equal to about 60 nautical miles.
The astronomical unit, equal to the mean radius of the earth's orbit or nearly 93,000,000 miles, is sometimes used in stating astronomical distances.
In stating interstellar distances it is some times found convenient by astronomers to use the light year, being the distance traversed by light in one year, or 65,700 astronomical units.
Besides the measures of length given above, there are numerous very special methods of denoting length in case of special commodities. The thickness of sheet iron and steel is denoted by a system of arbitrary gauge numbers. The numbers in use differ for different products. On 3 March 1893 Congress passed an act estab lishing a standard gauge for sheet and plate iron and steel for use in the customs service. In this system the gauge numbers indicate thick ness, or the weight per unit area. Sizes of wire are also denoted by a swial system of ar bitrary gauge numbers. The number of differ ent .ysterns which have been used is quite large. Pfeilsclunides 'Wire and Sheet Gauges of the World' gives comparative tables for 11 systems of wire gauges. At present the most common gauges in use in this country are the Brown and Sharp gauge and the Birmingham wire gauge. (See WIRE). The fineness or coarseness of yam is denoted by a system of numbers, called '''counts* which indicate usually the number of hanks of the yam in question which will weigh one pound. Thus No. 10 yarn (English cotton yarn and spun silk count) is a yarn of such fine ness that 10 hanks (of 84,000 yards) are re quired to make a weight of one pound, or again i No. 1 wool (Aberdeen count) is such that one spindle (of 14,400 yards) shall weigh a pound. There are about 24 different systems of counts in use, and in order to introduce uniformity in counting textile yarn throughout the world, the international metric count was approved by the International Paris Conference of 1900. Ac
cording to this count, No. 1 means that a length of 1 metre will weigh I gram, and 100 metres of No. 100 yarn will weigh 1 gram.
In addition to the above there are a large number of special systems of numbering par ticular commodities such as hats, shoes, gloves, nails, cordage, books and other articles, too numerous for description.
The units of superficial measure or area are usually the squares of the linear units and as such need but little comment. The circular mil (.7854 square mil) is the area of a circle .001 inch in diameter. One circular inch contains 1,000,000 circular mils, and one square inch con tains 1,273,240 circular mils. The square inch is the most common small unit of area, being used in measuring pressures, strength and other properties of materials, and in engraving, cloth analysis and many other purposes. The square foot (144 square inches) is also largely used. It is the basis of the board foot which is 144 cubic inches of undressed lumber, being reck oned as one square foot of one inch board. or its equivalent. The 'square' is a unit used in carpentry for flooring, ceiling and shingling, and contains 100 square feet, architects' and builders' measure.
In surveyors' measure 1 acre = 10 square = 160 square poles =100.000 square ter's or surveyors' links. The acre (43.560 square feet) was probably as much land as could be tilled in a day and therefore of rather indefi nite extent until later times. It is a unit of the same order as the French journie and the Ger man Morgen. The acres of various countries differ in size, for example, the Irish acre of 7,840 square yards; the Scottish acre of 6.104 square yards; the Cheshire acre of 10.240 square yards; Cunningham acre and the Imperial acre.
In subdividing public lands in the United States, the lands are laid out in townships.. One township= 36 sections or square miles =144 quarter sections= 23.040 acres. The 'home stead' is a free grant of public land having a maximum area of one-quarter section or 160 acres. In the Philippine Islands, the *home stead* is 64 hectares, which is almost identical with the homestead as defined above.