_Cuba_, February 28.--The most precious jewel of the Antilles is the Isle of Cuba, which we are now approaching. It is about seven hundred and ninety miles in length, its greatest width being one hundred and seven miles. The mountains add beauty and boldness to its scenery, the highest elevation on the island being about eight thousand feet. It was first discovered by the famous Columbus, in 1492, but not conquered from the Indians until 1511, at which time the Spaniards killed nearly five hundred thousand of the natives. From the following well-authenticated account we may be enabled to form some idea of the barbarity which characterized these movements: "One morning, as the Spaniards were tying an Indian cazique to the stake for the purpose of burning him alive, a Franciscan Friar approached, and informed him that if he would embrace their religion he should go to heaven, but if not he must burn in hell forever. The prince then asked him if there were any Spaniards in heaven. The friar responded in the affirmative--to which he replied, 'If that be so, I would rather be with the demons in hell than the Spaniards in heaven; for their cruelty is such that none can be more miserable than where they are.'" The cause of the Indians being so cruelly destroyed by the Spaniards was their covetous wish to possess the entire island, with its supposed wealth in silver and gold. Unfortunately, after they had murdered the Indians, their visionary dreams of vast fortunes were never realized, as very little precious metal was discovered, which many have supposed was a judgment on them for their cruelty. The soil in Cuba is itself a mine of wealth, on which can be produced from five to seven crops yearly, spring-time and harvest continuing all the season. There are mines of copper ore here, from which the early settlers made their cannon.