Ever since the invention of firearms sometime around the thirteenth century, ammunition makers struggled to make lead shots that were perfectly spherical. An obvious method was to pour molten lead into molds, but this was a laborious process that could produce only a limited number of shots at a time. Besides, it often left a seam where the two halves of the mould met, making the shots aerodynamically inefficient. Manufacturers tried pouring molten lead through a sieve suspended several inches above a barrel of water, but this often produced tear drop-shaped shots with a tail. Another method that was used until the early nineteenth century was to take small cubes of lead and agitate them in a barrel until the corners were knocked off and approximately round shot was produced. Yet, none of these methods were satisfactory while the demand for shot, both for military purposes and for sport, was continually growing.
The Remington Shot Tower in Bridgeport, the U.S. Photo credit
The breakthrough came in 1782 when a British plumber named William Watts, of Bristol, discovered that the key to producing perfectly round shots was to drop molten lead not from a few inches but from a great height. When liquids are dropped from a height, the surface tension of the liquid pulls them into a shape that has the least surface area, which happens to be a sphere. The higher the surface tension the more easily the liquid form into spheres, and lead, William Watts realized, has a surface tension far greater than that of water.
To put his idea into practice, Watts went back to his brick row house in Bristol and began adding floors to it. He cut holes in the floors of his house and dug a well beneath it to achieve the necessary drop. At the top, he poured molten lead through a sieve and as the lead fell it turned into spheres, just as he had predicted. By the time the drops hit the water below, they'd started to solidify. The water caught the shots and cooled them further. Watts applied for a patent and was granted. Soon, shot towers started appearing all over England and Europe.
The first major American urban shot tower was erected in Philadelphia in 1808, and by 1813, three big towers were operating near St. Louis. In subsequent years, shot towers advanced technologically and spread across the United States and Europe. Steam elevators replaced staircases, cast-iron frames buttressed brick walls, and mule-drawn carts made way for rail lines. Yet the manufacturing process itself has changed little. However, improvements such as the addition of an up flow of air dramatically shortened the drop required.
A memorial plaque at Clifton Hill Shot Tower. Photo credit
Further reduction in the drop occurred in 1961 with the invention of the Bliemeister method by Los Angeles based inventor Louis W. Bliemeister. In this method, molten lead is dripped from small orifices into a hot liquid instead of cold water, and then rolled along an incline. The temperature of the liquid controls the cooling rate of the lead, while the surface tension of the liquid and the inclined surface work together to turn the droplets of lead into a spherical form. Instead of tens of feet, the molten leads could be dropped from as little as 1 inch.
Shot towers became obsolete and gradually fell into disuse. Some of them were demolished but many of them are still standing and now preserved as architectural and industrial heritage. Watt's original shot tower, the one he built at his home, was taken over by the Sheldon Bush & Patent Shot Company in the 1860s' and kept producing shot until 1968. Sadly, it was demolished.
Notable Shot Towers
The tallest shot tower ever built still stands in the Melbourne suburb of Clifton Hill in Australia. This brick structure was built in 1882 and is 160 feet high. The Jackson Ferry Shot Tower, located in Wythe County, Virginia began construction around 1800. It was built of stone with walls almost a meter thick, as it was not practical to use brick in that region for such a large structure. The 75 foot tower was built at the edge of a cliff and utilized a subterranean shaft of the same length to double the overall height the lead would drop.
The Shot Tower on the South Bank of the River Thames in central London, England was constructed in 1826, and was in use until 1949, but was demolished to make way for the Queen Elizabeth Hall. Another square shot tower was also located not far away downstream along the Thames.
It’s hard to estimate how many shot towers were built and how many of them survive today. Some surviving examples of shot towers along with their pictures are published below.
Clifton Hill Shot Tower, the tallest shot tower ever built. Photo credit
Close-up of Clifton Hill Shot Tower. Photo credit
Chester Shot Tower located in the Boughton district of Chester, England. Built in 1799, the tower is the oldest such structure still standing in the world. Photo credit
Shot Ball Tower in Berlin. Photo credit
Cheese Lane Shot Tower in the English city of Bristol. It was built in 1969 as a replacement for the original tower built by William Watts. It now forms part of an office development and is located on the north bank of the Floating Harbour upstream of Castle Park. There is no public access to the interior of the tower. Photo credit
Coop's Shot Tower, encased by the Melbourne Central cone. The 50-meters tower was completed in 1888. The historic building was saved from demolition in 1973 and was incorporated into Melbourne Central complex in 1991 underneath an 84 m-high conical glass roof. Photo credit
This circular, sandstone shot tower, at Taroona, just south of Hobart, Tasmania, was built in 1870 and stands 48 metres tall. Photo credit
Inside the Taroona Shot Tower. Photo credit
Phoenix Shot Tower located near the downtown, Jonestown and Little Italy communities of East Baltimore, in Maryland. When it was completed in 1828 it was the tallest structure in the United States. Photo credit
The inside of the Phoenix Shot Tower, looking down from the 14th level. Photo credit
Shot Tower located in Dubuque, Iowa. Photo credit
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