14 JULY 1877, Page 3

The troops of the American Union have at last crossed

the frontier of Mexico in pursuit of marauders. They did not effect much, but the cavalry rode for a two days' march across the Rio Grande, and attacked Indians who are Mexican subjects. It is by no means yet clear that the Mexican Government has consented to these operations, though the Revolutionary Government has, and the Mexicans may insist on their Government remonstrating. It is probable that the Washington Cabinet, which does not want war, has calculated the chances ; but in all Spanish- American States the population is liable to fits of un- governable self-assertion, more especially about questions of inational honour. If the party in power should think that war, on the whole, was not for their disadvantage, there may be war yet between Mexico and the Union, and any war must be fol- lowed by annexations. Lower California is the only Mexican ,property which could be surrendered to pay expenses.