To take other instances of unsettled problems: How was pottery made in the Middle Ages--by travelling potters as in the East to-day, by gilds of potters, or by the inhabitants of the manor directly for their own use? Or again: When did the custom of building houses to let on rent first become general in England? It is clear that the habit of living in rented houses has and must have the most profound influence on family life and national character. But so far, neither from economic histories on the one hand nor from histories of architecture on the other, have I been able to obtain any reliable information on this point. When one turns to even more important questions--such, for instance, as the industrial position of women at different epochs--it is equally difficult to obtain precise and detailed knowledge. Without a very lengthy and elaborate investigation of the extant original materials, many of them scattered in municipal chambers in distant parts of England, it would be quite impossible to say on what terms women were admitted as members of the gilds and fraternities which extended over the whole area of industrial life in the Middle Ages. The character and organisation of the household and the position of women in the Middle Ages are subjects still practically untouched by the economic historians.[16] When we turn to modern times, a little more material has been collected. There is an investigation by the Board of Trade into the wages of domestic servants, and a book on domestic service by Professor Lucy Salmon of Vassar College. It deals of course mainly with American conditions, but cannot be neglected by any English student of the economic relations of the household. Humanitarianism has prompted studies more or less elaborate of the dietaries and housing conditions of the working classes, especially in towns,[17] but it would be idle to pretend that there has been yet more than a beginning made of the task of determining how for each class of the community its share of the national income as stated in money is translated into the necessaries, comforts, and luxuries of life, into house-room, fuel, food, cleanliness, clothing, insurance, domestic service, recreation, and culture. The generalisations available are of the most meagre description. We can, for instance, say with tolerable certainty that the agricultural labourer spends three-fourths of his income on food, the town labourer two-thirds, the artisan a half, the middle-class man from a third to a fourth; but there is practically no reliable information with regard to very large incomes, or to sums spent on clothing in _any_ section of the community.