(7) Lastly, the inferior mobility of woman as compared with man has an influence in reducing the average efficiency of her labour. On the one hand, women are more liable to have the locality of their home fixed by the requirements of the male worker in the family; on the other hand, they are physically less competent to undertake work far from their home. Hence they are far more narrowly restricted in their choice of work than men. They must often choose not that work they like best, or can do best, or which is most remunerative, but that which lies near at hand. This restriction implies that large numbers of women undertake low-skilled, low-paid, ineffective, and irregular work at their own homes or in some neighbouring work-room, instead of engaging in the more productive and more remunerative work of the large factories. Every limitation in freedom of choice of work signifies a reduction in the average effectiveness of labour. § 6. These elements of inferior physique and manual skill, lower intelligence and mental capacity, lack of education and knowledge of life, irregularity of work, more restricted freedom of choice, must in different degrees contribute to the inferior productivity of woman's industrial labour. In regarding this influence the experienced student of industrial questions hardly requires to be reminded that these must be regarded not merely as causes of low wages, but also as effects. This constant recognition of the interaction of the phenomena we are regarding as cause and effect is essential to a scientific conception of industrial society. Women are paid low wages because they are relatively inefficient workers, but they also are inefficient workers because they are paid low wages. While this smaller productivity diminishes the maximum wage attainable by women as compared with men, it is evident that many forces are at work which tend to equalise the productivity of men and women in industry: the evolution of machinery adapted to the weaker physique of women; the breakdown of customs excluding women from many occupations; the growth of restrictions upon male adult labour with regard to the working-day, etc., correspondent with those placed upon women; improved mobility of women's labour by cheaper and more facile transport in large cities; the recognition by a growing number of women that matrimony is not the only livelihood open to them, but that an industrial life is preferable and possible. These forces, unless counteracted by stronger moral and social forces, seem likely to raise the average productivity of women's industrial labour, and to incite her more and more to undertake industrial wage-work.