Burnham and Hammond carried their properties until 1930 and then sold them to the Mexican government .
The final blow to these efforts came in 1917 when Mexico passed laws prohibiting the sale of land to foreigners .
Burnham and Hammond carried their properties until 1930 and then sold them to the Mexico government .
The final blow to these efforts came in 1917 when Mexico passed laws prohibiting the sale of land to foreigners .