CARDENAS, CUBA, October 18, 1861.

Honorable R. M. T. HUNTER, Secretary of State.

SIR: I have the pleasure to apprise you of our safe arrival on the 16th instant at this port. We left Charleston at 1 a. m. on Saturday, 12th, as I told you we should do in my letter from there of the preceding day. Fortunately a rain came on at the moment of our departure which increasing the darkness the better enabled us to elude the blockading squadron.

We passed (as the captain reported) within a mile and a half of the nearest ship, the squadron then consisting of three steamers and a sloop-of-war (a sailing vessel). We could see their lights apparently not distant, but presume we escaped observation as we could see or hear no movement of the squadron. After we had passed them some three of four miles abandoning the coast we put directly out to sea and by the outer passage made direct for Nassau.

Off that port we learned from the pilots who came on board that there was no steam or other regular communication thence to Saint Thomas, the point of departure of the British steam line. We did not land therefore or cast anchor but put off at once for the Island of Cuba. I should have added that we reached Nassau about 4 p. m. on Monday.

At sea off the harbor of Cardenas we met with a small Spanish war steamer when we raised the Confederate flag and asked to speak them. Our salutation (by dipping our flag) as the vessels approached each other was courteously returned and the Spaniard laid to. Mr. Slidell, with Mr. Eustis, went on board, and on his return reported that he was received with great kindness and civility. We had been somewhat detained in finding our way over the shoal water of the Bahama Banks, and it being doubtful whether the coal remaining would take us to Havana it was determined to put into this port, the Spanish steamer kindly volunteering to attend and show us the way. We cast anchor off the town about 2 p. m., but our papers of clearance, &c., being directed to Havana, and there being some difficulty in getting the authorities together we did not effect a landing until the next day (yesterday). The custom-house officers, however, were civil and attentive, and as soon as the local governor could be appealed to he dispensed with all formalities, and ourselves and baggage landed without further difficulty or inspection.

I regret to say, however, that we shall have no steamer hence to Saint Thomas until November 9. The steamer for Cadiz once a month departed on its voyage from Havana the day of our arrival here. We shall thus be detained at Cuba some three weeks. The island is said to be healthy. We shall go to Havana or its neighborhood in a day or two and remain thereabouts until the time for our departure. We found a few Yankee vessels in port here, and learned that some of the captains loudly expressed their dissatisfaction at our being escorted into port by a Spanish man-of-war.

The Governor with some of the principal gentlement of the town have called on and proffered us every attention, and so far as we can gather opinions from conversation and on the streets the sympathies of the people are entirely with us. I would not omit to add that a Mr. Casanova, an acquaintance of Mr. Slidell, and who married a Virginia lady, learning at his plantation by a dispatch sent from here of our arrival came immediately to town by a ride of thirty miles on horse-back and cordially and urgently invited our entire party to visit him at his plantations, both of sugar and coffee, and become his guests during our stay on the island; and as further evidence of his kindness or