except in so far as they vary from employment to employment 279 4. Profits an element in Cost of Production, in so far as they vary from employment to employment.
5.
or are spread over unequal lengths of time
6. Occasional elements in Cost of Production: taxes, and scarcity value of materials
7. International values depend not solely on the quantities demanded, but also on the means of production available in each country for the supply of foreign markets.