the Great Comet of 1819, (C/1819 N1). It was the first comet analyzed using polarimetry, by François Arago. Steamboats The 1810s continued a trend of increasing commercial viability of steamboats in North America, following the early success of Robert Fulton and others in the preceding years. In 1811 the first in a continuously operating line of river steamboats left the dock at Pittsburgh to steam down the Ohio River to the Mississippi and on to New Orleans. Inventor John Stevens' boat, the Juliana, began operation as the first steam-powered ferry October 11, 1811, with service between New York, and Hoboken, New Jersey. John Molson's PS Accommodation was the first steamboat on the St. Lawrence and in Canada. Unlike Fulton, Molson did not show a profit. Molson had also two paddle steamboats "Swiftsure" of 1811 and "Malsham" of 1813 with engines by B&W. The experience of these vessels, especially that they could now offer a regular service, being independent of wind and weather, helped make the new system of propulsion commercially viable, and as a result its application to the more open waters of the Great Lakes was next considered. That idea went on hiatus due to the War of 1812. In a 25-day trip in 1815, the Enterprise further demonstrated the commercial potential of the steamboat with a 2,200-mile voyage from New Orleans to Pittsburgh.American Telegraph [Brownsville, Pa.], 5 July 1815: "Arrived at this port on Monday last, the Steam Boat Enterprize, Shreve, of Bridgeport, from New Orleans, in ballast, having discharged her cargo at Pittsburgh. She is the first steam boat that ever made the voyage to the Mouth of the Mississippi and back. She made the voyage from New Orleans to this port, in fifty four days, twenty days on which were employed in loading and unloading freight at different towns on the Mississippi and Ohio, so that she was only thirty four days in active service, in making her voyage, which our readers will remember must be performed against powerful currents, and is upwards of two thousand two hundred miles in length." In 1817, a consortium in Sackets Harbor, New York, funded the construction of the first US steamboat, Ontario, to run on Lake Ontario and the Great Lakes, beginning the growth of lake commercial and passenger traffic. The first commercially successful steamboat in Europe, Henry Bell's Comet of 1812, started a rapid expansion of steam services