We met with nothing remarkable until we were in the latitude of the river La Plata. Here there are violent gales from the southwest, called Pamperos, which are very destructive to the shipping in the river, and are felt for many leagues at sea. They are usually preceded by lightning. The captain told the mates to keep a bright lookout, and if they saw lightning at the southwest, to take in sail at once. We got the first touch of one during my watch on deck. I was walking in the lee gangway, and thought that I saw lightning on the lee bow. I told the second mate, who came over and looked out for some time. It was very black in the southwest, and in about ten minutes we saw a distinct flash. The wind, which had been southeast, had now left us, and it was dead calm. We sprang aloft immediately and furled the royals and top-gallant-sails, and took in the flying jib, hauled up the mainsail and trysail, squared the after yards, and awaited the attack. A huge mist capped with black clouds came driving towards us, extending over that portion of the horizon, and covering the stars, which shone brightly in the other part of the heavens. It came upon us at once with a blast, and a shower of hail and rain, which almost took our breath from us. The hardiest was obliged to turn his back. We let the halyards run, and fortunately were not taken aback. The little vessel ``paid off'' from the wind, and ran on for some time directly before it, tearing through the water with everything flying. Having called all hands, we close-reefed the topsails and trysail, furled the courses and jib, set the fore-topmast staysail, and brought her up nearly to her course, with the weather braces hauled in a little, to ease her.