Last Saturday a sloop arrived here from St. Eustatia with ten thousand weight of powder, the Master of which says that a large vessel had arrived there from Holland deeply loaded with arms and ammunition. He also says that the French ports in the West-Indies are open to us, and that the French men of war have orders to protect our vessels in and out of their harbours, that the French are fortifying Dunkirk which produced a remonstrance from the British Court, but without effect.