§ 2. #Rural and agricultural.# The adjectives rural and agricultural are often used loosely as synonyms. Agricultural refers primarily to the occupation of cultivating the soil, and is properly contrasted with other occupations, as mechanical and professional; whereas rural refers to place of residence outside of incorporated places of a specified minimum population (of late, 2500), and is properly contrasted with urban, applied to those living in larger population groupings. In 1910 the rural population comprised 53.7 per cent of the total population. It is true that the two groups of the agricultural and the rural populations are largely composed of the same persons, but to a considerable extent they are not. Many farm houses, together with part or all of the farm lands, lie inside urban boundaries, and, besides, some persons engaged in agriculture reside in urban places. On the other hand, any one acquainted in the least with a rural district (in the statistical sense) can at once think of many persons living there that are not engaged in agriculture; they may be merchants, warehousemen, railway employees, physicians, handicraftsmen, teachers, artists, retired business men, and others. The percentages given in this and in the preceding section indicate that about two fifths of the rural families are not engaged in agriculture. It is often important to make this distinction, tho it is difficult to do; for some of the much-discussed rural questions are of a broad social nature, are matters of rural sociology, relating pretty generally to the rural population; while other questions of "rural economics" are more strictly matters of agricultural economics and relate to the farm as a unit of industry, or to agriculture as an occupation.