When Madero was made President, the market price of the _Standard_ rose in Wall Street by 50 per cent. But this triumph did not last long. We are often astonished at the continual changes of front of the United States, which support the feeble Presidents in Mexico and oppose the energetic ones. By 1913 the _Daily Graphic_ and the _Vossische Zeitung_ had discovered the key to this mystery. Ever since Pearson obtained a footing in Mexico the _Standard_ has poured out gold in floods to drive out the British. It wishes to be the sole mistress of those immense oil-fields, which have turned out to be among the richest in the world. Only 54 million acres are being exploited at present, and already Mexico holds the second place in world production. Now the Mexican Minister of Industry and Commerce estimates the area of the oil-fields of that country at 150 million acres. Where will Mexico stand when all this territory is exploited? To arrest the progress of Pearson, the _Standard_ sent an emissary to Mexico to demand a monopoly of oil exploitation. It offered, in return, the immediate conclusion of a loan of 200 million Mexican dollars. Rockefeller's envoy promised, moreover, that the revolution would die down as though by magic, while, in case of refusal, it would continue until General Huerta was replaced by a more tractable President who would submit to American requirements. Like his predecessor, Porfirio Diaz, General Huerta refused to make Mexico the vassal of the great trust, and the insurrection redoubled in violence.[16] Tired of the continual struggles which ravaged their country for the benefit of the two great Anglo-Saxon nations, the Mexicans resolved to profit by the European War to win their freedom for ever. According to the laws of the country (1884, 1892, 1910) the owner of the surface was also the owner of the subsoil. All that a company had to do was to buy the ground and it was at peace with God and man. The Constitution of 1917 disturbed this peace. "The subsoil," it declared, "belongs to the nation." To exploit petroleum deposits a Government permit was required. This permit is only to be granted to Mexicans or to foreigners who consent to submit to the laws of the country as natives, and thus renounce their privileges as foreigners.