Dangers of Ignorance.—The immigrant ship Win. Nelson was recently destroyed off our coast by the captain fumigating his vessel as-he approached port, with.pitch, into which were thrust red hot irons. The pitch took fire, the ship was destroyed, and, with the exception of a few persons, including the captain and the other officers, all the passengers nearly—over four hundred persons—were burned to death or went down with the hulk. It is a very common practice of shipmasters to fumigate their vessels to rid them of disease and vermin. The latter is usually done at the wharves, but the former before they reach port to disinfect and present a clean bill of health to pass quarantine. This being an immigrant ship, it is likely that it was infected with fever, an evidence first of carelessness in the chief officer, who should see cleanliness observed, and preserve thereby the health of the ship.— He should have known that chloride of lime would have disinfected the vessel without any danger. It is surprising that with common schools and the spread of knowledge that so simple a fact should not be known to those who have the safety of human lives so entirely in their charge, and that such blundering practices as burning inflammatory substances to disinfect a ship should be still resorted to. The regulations for ajship should require printed rules to be hung up, giving such information, as well as directions to the passengers for the preservation of health. Proper attention from the officers to see these rules enforced, and making themselves thoroughly acquainted with the knowledge which will conduce to comfort and safety of their living freight, would save many lives now exposed by disease ajad accident in a ship sailed by an incompetent master.—Phila, J^edger,