line was projected to Copiapo--which is at the head of the province whose silver deposits have yielded so abundantly of late: it is said that the export from that province for the year will amount to six millions of dollars. Coal, said to be very little inferior to the best English coal, is found at Talcahuana. Labor and the necessaries of life were very high at Valparaiso.----From _Montevideo_, accounts to the 5th of June, state that the ratification of the Brazilian treaties puts an end to all fear of another foreign war. The principal clauses of the Convention agreed upon are the abandonment of the line of frontier which the treaties of October, 1851, conceded to Brazil, and the cession of the right of free navigation on Lake Merim to the Oriental flag. MEXICO. The Mexican Republic is again agitated by threatening insurrections in various quarters, which the central government finds itself powerless to quell. In Mazatlan and Guadalajara strong bodies of insurgents, supported by the National Guard, have maintained themselves against the government, which opposes them by decrees and commercial regulations instead of troops. Upon the frontier the ravages of the Indians continue to be most destructive. The government has invited proposals for the construction of a road across the isthmus of Tehuantepec, and seems determined to resist the demands of the United States for the recognition of the Garay grant. The Mexican papers contain copious accounts of local disturbances and insurrections, the details of which it is needless here to repeat. The condition of the country is difficult and precarious in the extreme. Rumors have been circulated of endeavors to secure the intervention of England and France, in order to give greater strength and stability to the government, and enable it to resist encroachments constantly apprehended from the United States: but there is no reason to believe they have as yet proved successful. CUBA. The colonial government of Cuba has discovered new and formidable conspiracies against the Spanish authority in that island, and has made numerous arrests of suspected parties. During the months of June and July several numbers were clandestinely published and widely circulated, of a paper called _The Voice of the People_, the object of which was to arouse the Cubans to resistance of the Spanish rule. For some time the efforts of the authorities to detect its editors, or the place of its publication, were ineffectual: but both were finally betrayed by parties who had become acquainted with them. The principal editor, however, had previously escaped to the United States. Nearly all engaged upon it, so far as known, were either native Cubans or Spaniards. The cholera was very prevalent and destructive at Havana, at our latest dates. GREAT BRITAIN.