Skc. 5] INCOME SUMMATION 151 is willing to suffer solely because of the shelter he receives. This shelter alone remains as the income from the house after the rent transaction is canceled out between the two parties concerned. The shelter-income is the essential and abiding item, and without it there could be no rent-income to the landlord. Again, a railway yields as its income solely the natural one of transporting goods and passengers. Its owners sell this transportation service for money and regard the rail- way simply as a money maker; but to the shippers and passengers this same money is an expense and exactly off- sets the railway’s money earnings. Of the three items — money income of the road, money outgo of its patrons, and transportation — the first two mutually cancel and leave only the third, transportation, as the real contribu- tion of the railway to the sum total of income. We see, then, that the method of couples, applied to buyer and seller, denudes all capital of its so-called “money-income,” and lays bare the only income it can really produce, the natural income. We see that capital is not a money-making machine, but that its income to society is simply its services of production, transporta- tion, and gratification. The income from the farm is the yielding of its crops; from the mine, the production of its ore; from the factory, its transformation of raw into fin- ished products; from commercial capital, its passage of goods from producer to consumer; from articles in con- sumers’ hands, their enjoyment or so-called “ consumption.” Similar principles apply to outgo, no part of which, for society, exists in money form. The great bulk of what mer- chants call “ cost of production,” expense, or outgo, consists of money costs which carry with them their own cancella- tion. For manufacturers, merchants, and other business men, almost every outgo is an expense, i.e. consists of a money payment. Such money payments are for wages, raw materials, rent, and interest charges. Now all these