Let us next subject to analysis the incidence of the so-called taxation of land. Considered _per se_ (or in itself), land, in common with unappropriated air and water, has no value; and it can not in any strict sense be affirmed that we tax land; and when such affirmation is made, its only legitimate and justifiable meaning is that we tax the value of land; which value is due entirely to the amount of personal property (in the sense of embodied labor) expended upon it, and the pressure or demand of such property or labor to use, possess, and occupy it. Vattel, in his Law of Nations, enunciates as a self-evident and irrefutable proposition that "Nature has not herself established property, and in particular with regard to lands. She only approves this introduction for the advantage of the human race." One of the most striking examples of evidence in illustration and proof of this proposition is to be found in an incident, which has heretofore escaped attention, which occurred during a debate in the Senate of the United States in 1890 on a bill for revision of duties on imports, in respect to the article borax (borate of soda). Formerly the world's supply of this mineral substance, which enters largely into industrial processes and medicine, was limited, and mainly derived from certain hot springs in Tuscany, Italy; but within a comparatively recent period it has been found that it exists in such abundance in certain of the desert regions of California, Nevada, and Arizona, that it can be gathered with the minimum of labor from the very surface of the ground. Were a single acre of similar desert to be found in any section of a country enjoying the most ordinary privileges in respect to transportation and water supply, it would be a source of wealth to its proprietor. But under existing circumstances, although thousands and thousands of acres of this land can be bought with certain title from its owner--the Federal Government--for two dollars and twenty-five cents an acre, no one wants it at any price; and the prospective demand for it has not yet been sufficient to warrant the Government in instituting even a survey as a preliminary to effecting a sale. In the Senate debate above alluded to it was proposed to increase the duty on imported borax, with the expectation that a consequent increase in its domestic price would afford sufficient profit to induce such construction of roads and such a supply of water and labor on the borax tracts of the deserts as to enable them to become property.[13]