This is a Hale 24-pounder war rocket of ca. 1865-1870, a type of gunpowder-propelled "stickless" war rocket developed by the Englishman William Hale to eliminate the long and cumbersome wooden guidesticks of other war rockets. He invented the stickless rocket in 1844. It was evolved over the years until the final pattern shown here.
The exhaust gases were used to both propell the rocket and caused it to rotate in flight by impinging on curved exhaust vanes in the rear. The spinning helped deflect any wind and kept the rocket on course. This specimen was fired on a firing range about 1867 as a practice round, but was recovered in 1974 and then restored. It was donated to the Smithsonian in 1974 by the Royal Artillery Institute, U.K.
This object is on display in Rockets & Missiles at the Steven F. Udvar-Hazy Center in Chantilly, VA.