Solar (unit)
Solar was a Mexican square measure.
It was not one of the Spanish measurements that were generally used here. The full name of the measure was Solar para casa . The introduction of a uniform value as early as 1845 for the Vara (mexicana) with 838 millimeters had an effect on all derived measurements, including solar ones. On March 15, 1857, a law was passed according to which the new French system of metric measurements should apply from January 1, 1862.