Let the principle be tested by Money measurements. Will any sane man pay $100 to satisfy any Economic desire of his which he knows he can satisfy as perfectly for $75, or $80, or $90, or even more than $90 so it be less than $100? Certainly not. Then the Economic law in question may be expressed in terms of Money. Instead of saying that men seek to satisfy their Economic desires with least exertion, we may express the same natural law by saying that men seek to satisfy their Economic desires at the lowest Money cost. Both statements have the same meaning. The only difference between them is that the latter is expressed in terms of Money measurement whereas the former is expressed in terms of human effort. Another familiar demonstration of this natural Economic law that men both individually and in the mass seek to satisfy their Economic desires with least exertion, is the human craving for Labor-saving invention. Could any more comprehensive exemplification of the natural law in question be demanded? Why does mankind crave Labor-saving methods for producing Artificial Objects from and upon Natural Resources, if there be no law of human nature which impels mankind to seek satisfaction of Economic desires with least exertion? John Orr concisely sums up this Economic law in these words: “Very strong and deep is the desire of men to find the easiest way of doing things.”[4] [4] “Short History of British Agriculture,” By John Orr. Oxford University Press, 1922. The earliest expression of this principle was by Henry George in 1879. Alluding to Political Economy, the term by which Economics was then identified, he wrote: “It lays its foundations upon firm ground. The premises from which it makes its deductions are truths which have the highest sanction; axioms which we all recognize; upon which we safely base the reasoning and actions of every-day life, and which may be reduced to the metaphysical expression of the physical law that motion seeks the line of least resistance--viz., that men seek to gratify their desires with the least exertion.”[5] [5] “Progress and Poverty: An Inquiry into the Cause of Industrial Depressions, and of Increase of Want With Increase of Wealth. The Remedy.” By Henry George. New York: D. Appleton and Company. 1883.