From The U.S. Gazette.

MELANCHOLY ACCIDENT — Yesterday afternoon, (Wednesday 5 ^th inst.) about 5 o’clock P.M. just as the William Penn, with about 150 passengers, from Baltimore, had come round the point, below this city, (Philadelphia,) she was discovered to be on fire near the furnace. The rapidity of her motion creating a strong draft, and the very combustible nature of every piece of wood near the fire, soon rendered it certain that the boat would be lost. She was accordingly run ashore on the muddy margin of the river, before reaching which she seemed to be in one full blaze. Here the passengers jumped out; and most of their baggage and part of the great Southern Mail were thrown ashore. Many of the passengers jumped overboard. A steamboat went down and brought up from the wreck most of the passengers to the usual landing place.

We learned late Wednesday evening, that the dead bodies of a gentleman and lady were taken from the river.

Several lives were saved by the hazardous exertions of persons belonging to the boat, and by those who were drawn to the scene. From the great number of passengers, and the confusion consequent on such an awful scene, it was impossible to ascertain with any degree of certainty the extent of personal injury sustained.

Some of the passengers stripped themselves, jumped into the river and swam ashore—they were taken up almost perishing from the cold.

It was mentioned to us that a lady in company with the Rev. Dr. Mitchellmore, of Lewistown, Del. jumped into the river in her consternation. Mr. M. followed her and was drowned. At our last information hopes were entertained of recovering the lady.

Col. Joseph S. Porter is among the drowned.

One man drifted out into the river on a settee, but was finally saved.

When the boat was run ashore, she run with her bows into the mid, and her stern in deep water—the fire was raging so intensely in the centre of the boat, as to prevent the passengers who were aft, from going forward—they therefore jumped into the water beyond their depth.

We regret to add, the lady mentioned above, died between 8 and 9 o’clock. She was in a delicate state of health. The body has been removed by the Coroner to Cherry Hill, where it will remain for a short time, for recognition.

The fire took in the wood house. The boat was burnt to the water’s edge—the loss sustained is about $70,000.