Alfred Marshall — English Economist born on July 26, 1842, died on July 13, 1924

Alfred Marshall was one of the most influential economists of his time. His book, Principles of Economics , was the dominant economic textbook in England for many years. It brings the ideas of supply and demand, marginal utility, and costs of production into a coherent whole. He is known as one of the founders of neoclassical economics... (wikipedia)

The price of every thing rises and falls from time to time and place to place; and with every such change the purchasing power of money changes so far as that thing goes.
Capital is that part of wealth which is devoted to obtaining further wealth.
Consumption may be regarded as negative production.
Civilized countries generally adopt gold or silver or both as money.
All labour is directed towards producing some effect.