In the first place, they may be classified thus: into things that are wealth because they are consumed, things that are wealth because they are owned, and things that are wealth because they are used or occupied. Under the first heading come food, clothing, lighting, and fuel; under the second, movable chattels; and under the third, the occupation of houses,[16] the services of domestics, the carrying of letters by the Post Office, transport and travelling, and the defences and administration of the country. In other words, the first class consists of new perishable goods, the second of new durable goods, and the third not of goods at all, but of services and uses. The relative amounts of value of the three will be shown with sufficient accuracy by the following rough estimates. Of a total of _eleven hundred and seventy million pounds_, perishable goods count for _five hundred and twenty million pounds_, durable goods and chattels for _two hundred and fifty million pounds_, and services and uses for _four hundred million pounds_. Thus, less than a quarter of what we call the national income consists of material things which we can keep and collect about us; little less than half consists of material things which are only produced to perish, and perish almost as fast as they are made; and more than a third consists of actions and services which are not material at all, and pass away and renew themselves even faster than food and fuel. [Sidenote ◆1 A large part of the national income consists of things that are imported.] [Sidenote ◆2 Most of our food is imported.]